governance: fetch delegation before governance proposal start epoch

[Fraccaman]

Describe your changes

Closes #3937

Checklist before merging

• If this PR has some consensus breaking changes, I added the corresponding breaking:: labels
  • This will require 2 reviewers to approve the changes
• If this PR requires changes to the docs or specs, a corresponding PR is opened in the namada-docs repo
  • Relevant PR if applies:
• If this PR affects services such as namada-indexer or namada-masp-indexer, a corresponding PR is opened in that repo
  • Relevant PR if applies:

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 9 lines in your changes missing coverage. Please review.

Project coverage is 73.20%. Comparing base (602d154) to head (49fc433).
Report is 290 commits behind head on main.

Files with missing lines	Patch %	Lines
wasm/tx_vote_proposal/src/lib.rs	0.00%	9 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4032   +/-   ##
=======================================
  Coverage   73.20%   73.20%           
=======================================
  Files         341      341           
  Lines      105151   105158    +7     
=======================================
+ Hits        76978    76984    +6     
- Misses      28173    28174    +1     

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