refactor: remove simapp from x/staking module (#13101)

## Description

Closes: #13099 



---

### Author Checklist

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- [ ] added `!` to the type prefix if API or client breaking change
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- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
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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 
- [ ] reviewed state machine logic
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- [ ] manually tested (if applicable)

testutil/sims/weights.go

@@ -1,26 +0,0 @@
-package sims
-
-// Default simulation operation weights for messages and gov proposals
-const (
-	DefaultWeightMsgSend                        int = 100
-	DefaultWeightMsgMultiSend                   int = 10
-	DefaultWeightMsgSetWithdrawAddress          int = 50
-	DefaultWeightMsgWithdrawDelegationReward    int = 50
-	DefaultWeightMsgWithdrawValidatorCommission int = 50
-	DefaultWeightMsgFundCommunityPool           int = 50
-	DefaultWeightMsgUnjail                      int = 100
-	DefaultWeightMsgCreateValidator             int = 100
-	DefaultWeightMsgEditValidator               int = 5
-	DefaultWeightMsgDelegate                    int = 100
-	DefaultWeightMsgUndelegate                  int = 100
-	DefaultWeightMsgBeginRedelegate             int = 100
-	DefaultWeightMsgCancelUnbondingDelegation   int = 100
-
-	DefaultWeightCommunitySpendProposal int = 5
-	DefaultWeightTextProposal           int = 5
-	DefaultWeightParamChangeProposal    int = 5
-
-	// feegrant
-	DefaultWeightGrantAllowance  int = 100
-	DefaultWeightRevokeAllowance int = 100
-)