namada/wasm/cache: write the file to cache before updating progress

[tzemanovic]

Describe your changes

Indicate on which release or other PRs this topic is based on

v0.34.0

Checklist before merging to draft

• [x] I have added a changelog
• [x] Git history is in acceptable state

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 59.40%. Comparing base (9d4de02) to head (4fb6d12). Report is 12 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3181      +/-   ##
==========================================
- Coverage   59.40%   59.40%   -0.01%     
==========================================
  Files         298      298              
  Lines       92326    92329       +3     
==========================================
- Hits        54849    54848       -1     
- Misses      37477    37481       +4     

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