Bump flake8-pyi to 24.6.0 (#12132)

.flake8

@@ -8,10 +8,6 @@ extend-ignore = Y090
 per-file-ignores =
   # We should only need to noqa Y and F821 codes in .pyi files
   *.py: NQA
-  # Ignore Y052 in this file: there are loads of false positives
-  # due to the fact that flake8-pyi doesn't understand subclasses of `CoerciveEnum`
-  # as being enum classes
-  stubs/fpdf2/fpdf/enums.pyi: Y052
   # Generated protobuf files:
   # Y021: Include docstrings
   # Y023: Alias typing as typing_extensions