refactor: separate DeclareV2::new_with_sierra_class_hash

[Oppen]

Create a new method for passing the Sierra class hash to the DeclareV2 constructor.
This is done for two reasons:

1. It avoids unnecessary breakage
2. Makes the error prone usage explicit and opt-in, as passing the wrong hash would result in incorrect behavior

Checklist

• Linked to Github Issue
• Unit tests added
• Integration tests added.
• This change requires new documentation.
  • Documentation has been added/updated.

[codecov-commenter]

Codecov Report

Merging #807 (d39749e) into main (dce8b59) will decrease coverage by 0.08%.
The diff coverage is 31.74%.

@@            Coverage Diff             @@
##             main     #807      +/-   ##
==========================================
- Coverage   91.77%   91.70%   -0.08%     
==========================================
  Files          52       52              
  Lines       12297    12346      +49     
==========================================
+ Hits        11286    11322      +36     
- Misses       1011     1024      +13     

Impacted Files	Coverage Δ
src/transaction/declare_v2.rs	74.05% <31.74%> (-1.44%)	⬇️

... and 8 files with indirect coverage changes