Add pre-propose-approval support for multiple choice proposals, and freeze approver

[NoahSaso]

this does two things:

1. it creates a dao-pre-propose-approval-multiple contract so that multiple choice proposal modules can have approvers, just like single choice proposal modules. it also ensures the approver contract works for both approval-single and approval-multiple

2. it freezes the approver in the proposal so that a previously created pending proposal does not change approvers if the approver gets updated while it's still pending. this maintains consistency with other DAO logic to keep things intuitive, where the members who can vote on a proposal are frozen upon proposal creation.

[codecov]

Codecov Report

Attention: Patch coverage is 97.86788% with 61 lines in your changes missing coverage. Please review.

Project coverage is 96.65%. Comparing base (340b1e1) to head (91d5e8b).
Report is 1 commits behind head on development.

Files with missing lines	Patch %	Lines
...se/dao-pre-propose-approval-single/src/contract.rs	52.38%	50 Missing ⚠️
.../dao-pre-propose-approval-multiple/src/contract.rs	96.97%	9 Missing ⚠️
...opose/dao-pre-propose-approval-multiple/src/msg.rs	75.00%	1 Missing ⚠️
...ose/dao-pre-propose-approval-multiple/src/tests.rs	99.95%	1 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           development     #883      +/-   ##
===============================================
- Coverage        96.67%   96.65%   -0.03%     
===============================================
  Files              241      245       +4     
  Lines            65993    67224    +1231     
===============================================
+ Hits             63802    64974    +1172     
- Misses            2191     2250      +59     

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[bekauz]

this looks great, I don't have much to add.

maybe except that the dao_pre_propose_base design combined with message extensions is super clean and holding up really well!