refactor!: change GetSigners return type to []sdk.AccAddress (#9915)

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## Description
Changes the `sdk.Msg` interface method `GetSigners() []string` to `GetSigners() []sdk.AccAddress`

Closes: #9885 


+change GetSigner return type
+defer address checking to each msg's `ValidateBasic`  method
+clean up consistency/redundancy issues in validate basic


---

### Author Checklist

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please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

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your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

baseapp/baseapp.go

@@ -19,7 +19,6 @@ import (
 	"github.com/cosmos/cosmos-sdk/store/rootmulti"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
-	sdktx "github.com/cosmos/cosmos-sdk/types/tx"
 	"github.com/cosmos/cosmos-sdk/x/auth/migrations/legacytx"
 )
 
@@ -511,7 +510,7 @@ func validateBasicTxMsgs(msgs []sdk.Msg) error {
 	}
 
 	for _, msg := range msgs {
-		err := sdktx.ValidateMsg(msg)
+		err := msg.ValidateBasic()
 		if err != nil {
 			return err
 		}

baseapp/baseapp_test.go

@@ -717,10 +717,10 @@ func (msg msgCounter) String() string { return "TODO" }
 func (msg msgCounter) ProtoMessage()  {}
 
 // Implements Msg
-func (msg msgCounter) Route() string        { return routeMsgCounter }
-func (msg msgCounter) Type() string         { return "counter1" }
-func (msg msgCounter) GetSignBytes() []byte { return nil }
-func (msg msgCounter) GetSigners() []string { return nil }
+func (msg msgCounter) Route() string                { return routeMsgCounter }
+func (msg msgCounter) Type() string                 { return "counter1" }
+func (msg msgCounter) GetSignBytes() []byte         { return nil }
+func (msg msgCounter) GetSigners() []sdk.AccAddress { return nil }
 func (msg msgCounter) ValidateBasic() error {
 	if msg.Counter >= 0 {
 		return nil
@@ -762,10 +762,10 @@ func (msg msgCounter2) String() string { return "TODO" }
 func (msg msgCounter2) ProtoMessage()  {}
 
 // Implements Msg
-func (msg msgCounter2) Route() string        { return routeMsgCounter2 }
-func (msg msgCounter2) Type() string         { return "counter2" }
-func (msg msgCounter2) GetSignBytes() []byte { return nil }
-func (msg msgCounter2) GetSigners() []string { return nil }
+func (msg msgCounter2) Route() string                { return routeMsgCounter2 }
+func (msg msgCounter2) Type() string                 { return "counter2" }
+func (msg msgCounter2) GetSignBytes() []byte         { return nil }
+func (msg msgCounter2) GetSigners() []sdk.AccAddress { return nil }
 func (msg msgCounter2) ValidateBasic() error {
 	if msg.Counter >= 0 {
 		return nil
@@ -779,13 +779,13 @@ type msgKeyValue struct {
 	Value []byte
 }
 
-func (msg msgKeyValue) Reset()               {}
-func (msg msgKeyValue) String() string       { return "TODO" }
-func (msg msgKeyValue) ProtoMessage()        {}
-func (msg msgKeyValue) Route() string        { return routeMsgKeyValue }
-func (msg msgKeyValue) Type() string         { return "keyValue" }
-func (msg msgKeyValue) GetSignBytes() []byte { return nil }
-func (msg msgKeyValue) GetSigners() []string { return nil }
+func (msg msgKeyValue) Reset()                       {}
+func (msg msgKeyValue) String() string               { return "TODO" }
+func (msg msgKeyValue) ProtoMessage()                {}
+func (msg msgKeyValue) Route() string                { return routeMsgKeyValue }
+func (msg msgKeyValue) Type() string                 { return "keyValue" }
+func (msg msgKeyValue) GetSignBytes() []byte         { return nil }
+func (msg msgKeyValue) GetSigners() []sdk.AccAddress { return nil }
 func (msg msgKeyValue) ValidateBasic() error {
 	if msg.Key == nil {
 		return sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "key cannot be nil")