tools: remove readability/fn_size error throw

Follow up #54663

Author: RafaelGSS

tools/cpplint.py

@@ -1585,11 +1585,6 @@ def Check(self, error, filename, linenum):
       # 50 => 0, 100 => 1, 200 => 2, 400 => 3, 800 => 4, 1600 => 5, ...
       if error_level > 5:
         error_level = 5
-      error(filename, linenum, 'readability/fn_size', error_level,
-            'Small and focused functions are preferred:'
-            ' %s has %d non-comment lines'
-            ' (error triggered by exceeding %d lines).'  % (
-                self.current_function, self.lines_in_function, trigger))
 
   def End(self):
     """Stop analyzing function body."""