fix: Use INSUFFICIENT_RESOURCES_FOR_VALIDATE instead of INSUFFICIENT_MAX_FEE in v8

[hudem1]

Solves issue #2391

Note: In the rpccore.go file, now the 2 errors INSUFFICIENT_MAX_FEE and INSUFFICIENT_RESOURCES_FOR_VALIDATE have the same code (53), but they are never both used in the same pkg

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.76%. Comparing base (00168b1) to head (6c6034f).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2457      +/-   ##
==========================================
+ Coverage   73.66%   73.76%   +0.10%     
==========================================
  Files         138      138              
  Lines       16919    16918       -1     
==========================================
+ Hits        12463    12480      +17     
+ Misses       3587     3574      -13     
+ Partials      869      864       -5     

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