fix: TxFactory reads from --fee-{payer,granter} (#12127)

## Description

It seems like we added `--fee-payer` and `--fee-granter` flags to the CLI, but when generating a tx, they are ignored.

ref: #11880



---

### Author Checklist

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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/main/CONTRIBUTING.md#pr-targeting))
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- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/main/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/main/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
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### 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 
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- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

x/feegrant/client/testutil/suite.go

@@ -750,17 +750,55 @@ func (s *IntegrationTestSuite) TestTxWithFeeGrant() {
 	_, err = s.network.WaitForHeight(1)
 	s.Require().NoError(err)
 
-	// granted fee allowance for an account which is not in state and creating
-	// any tx with it by using --fee-account shouldn't fail
-	out, err := govtestutil.MsgSubmitLegacyProposal(val.ClientCtx, grantee.String(),
-		"Text Proposal", "No desc", govv1beta1.ProposalTypeText,
-		fmt.Sprintf("--%s=%s", flags.FlagFeeGranter, granter.String()),
-	)
+	testcases := []struct {
+		name       string
+		from       string
+		flags      []string
+		expErrCode uint32
+	}{
+		{
+			name:  "granted fee allowance for an account which is not in state and creating any tx with it by using --fee-granter shouldn't fail",
+			from:  grantee.String(),
+			flags: []string{fmt.Sprintf("--%s=%s", flags.FlagFeeGranter, granter.String())},
+		},
+		{
+			name:       "--fee-payer should also sign the tx (direct)",
+			from:       grantee.String(),
+			flags:      []string{fmt.Sprintf("--%s=%s", flags.FlagFeePayer, granter.String())},
+			expErrCode: 4,
+		},
+		{
+			name: "--fee-payer should also sign the tx (amino-json)",
+			from: grantee.String(),
+			flags: []string{
+				fmt.Sprintf("--%s=%s", flags.FlagFeePayer, granter.String()),
+				fmt.Sprintf("--%s=%s", flags.FlagSignMode, flags.SignModeLegacyAminoJSON),
+			},
+			expErrCode: 4,
+		},
+		{
+			name: "use --fee-payer and --fee-granter together works",
+			from: grantee.String(),
+			flags: []string{
+				fmt.Sprintf("--%s=%s", flags.FlagFeePayer, grantee.String()),
+				fmt.Sprintf("--%s=%s", flags.FlagFeeGranter, granter.String())},
+		},
+	}
+
+	for _, tc := range testcases {
+		s.Run(tc.name, func() {
+			out, err := govtestutil.MsgSubmitLegacyProposal(val.ClientCtx, tc.from,
+				"Text Proposal", "No desc", govv1beta1.ProposalTypeText,
+				tc.flags...,
+			)
+			s.Require().NoError(err)
+
+			var resp sdk.TxResponse
+			s.Require().NoError(clientCtx.Codec.UnmarshalJSON(out.Bytes(), &resp), out.String())
+			s.Require().Equal(tc.expErrCode, resp.Code, resp)
+		})
+	}
 
-	s.Require().NoError(err)
-	var resp sdk.TxResponse
-	s.Require().NoError(clientCtx.Codec.UnmarshalJSON(out.Bytes(), &resp), out.String())
-	s.Require().Equal(uint32(0), resp.Code)
 }
 
 func (s *IntegrationTestSuite) TestFilteredFeeAllowance() {