[python-package] fix mypy error about pyarrow data (#6333)

.ci/test.sh

@@ -76,6 +76,7 @@ if [[ $TASK == "lint" ]]; then
         cpplint \
         mypy \
         'pre-commit>=3.6.0' \
+        'pyarrow>=14.0' \
         'r-lintr>=3.1'
     source activate $CONDA_ENV
     echo "Linting Python code"

python-package/lightgbm/basic.py

@@ -364,7 +364,7 @@ def _is_2d_collection(data: Any) -> bool:
     )
 
 
-def _is_pyarrow_array(data: Any) -> bool:
+def _is_pyarrow_array(data: Any) -> "TypeGuard[Union[pa_Array, pa_ChunkedArray]]":
     """Check whether data is a PyArrow array."""
     return isinstance(data, (pa_Array, pa_ChunkedArray))