feat: increase the CLI test coverage

[hedgar2017]

Increases the CLI test coverage to nearly 100%.

Checklist

• PR title corresponds to the body of PR.
• Tests for the changes have been added / updated.
• Documentation comments have been added / updated.
• Code has been formatted via cargo fmt and checked with cargo clippy.

[codecov]

Codecov Report

Attention: Patch coverage is 91.47727% with 15 lines in your changes missing coverage. Please review.

Project coverage is 72.81%. Comparing base (7684c93) to head (dbad9ee).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/project/mod.rs	57.89%	8 Missing ⚠️
src/vyper/mod.rs	76.47%	4 Missing ⚠️
src/build/mod.rs	88.88%	2 Missing ⚠️
src/build/contract.rs	95.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #139      +/-   ##
==========================================
+ Coverage   64.24%   72.81%   +8.57%     
==========================================
  Files          53       53              
  Lines        4410     4381      -29     
==========================================
+ Hits         2833     3190     +357     
+ Misses       1577     1191     -386     

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[PavelKopyl]

LGTM.