Fix bytecode is not written when starknet contract already exists

[ClementWalter]

Time spent on this PR: 0.3

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Resolves #821

What is the new behavior?

Overwrite bytecode if stored bytecode len doesn't match account.code_len

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (4c10873) 71.90% compared to head (fe40997) 71.84%.
Report is 1 commits behind head on main.

Files	Patch %	Lines
src/data_availability/starknet.cairo	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #822      +/-   ##
==========================================
- Coverage   71.90%   71.84%   -0.06%     
==========================================
  Files          47       47              
  Lines        6041     6046       +5     
==========================================
  Hits         4344     4344              
- Misses       1697     1702       +5     

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