[KGA-100] [KGA-56] fix: memory expansion early return condition

[enitrat]

Fixes the early return condition in calculate_gas_extend_memory that was off-by-one.
This had no impact on the code, as the correct memory was computed after. This just did not early returned in all cases.

code-423n4/2024-09-kakarot-findings#101
code-423n4/2024-09-kakarot-findings#78

[notion-workspace]

Current memory length is computed incorrectly inside calculate_gas_extend_memory

[notion-workspace]

Memory can still be charged for even if there is no expansion

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.7%. Comparing base (5cdbb52) to head (81b2f3f).
Report is 9 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1619     +/-   ##
=======================================
- Coverage   64.0%   63.7%   -0.3%     
=======================================
  Files         44      44             
  Lines       8363    8363             
=======================================
- Hits        5354    5331     -23     
- Misses      3009    3032     +23     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests
• JS Bundle Analysis - Avoid shipping oversized bundles