Code optimization recommendations

[grarco]

Reported by Informal Systems.

Description

Upon reviewing the codebase, several optimizations were identified that could enhance the efficiency and readability of the code.

Problem Scenarios

1. The validate_tx function is redundantly called twice in the check_proposal_tx function, during
   process proposal, leading to unnecessary overhead. 1st: /process_proposal.rs#L249-L256
   2nd: /process_proposal.rs#L265-L270
2. The previously defined inner_tx_hash should be used instead of &tx.raw_header_hash() .
   mempool_validation()
3. Move parameter obtaining from storage outside loop iterations to minimize unnecessary storage calls. In this way, the number of calls to storage would be reduced. /governance.rs#L79
4. Since the validate_wrapper_bytes function is specific to Wrapper transactions, the transaction type check should be performed at the beginning of the function. If the transaction is not a WrapperTx, an error
   should be immediately returned. /prepare_proposal.rs#L286

Recommendation

To improve performance, it is recommended to implement the suggestions outlined in the Problem Scenarios section.