Revert "Remove ignore of deprecated Ruff rule"

This reverts commit 19d13a0.

Author: VeckoTheGecko

pyproject.toml

@@ -169,6 +169,8 @@ ignore = [
     "RUF005",
     # Prefer `next(iter(variable.items()))` over single element slice
     "RUF015",
+    # Use `X | Y` in `isinstance` (see https://github.com/home-assistant/core/issues/123850)
+    "UP038",
     "RUF046", # Value being cast to `int` is already an integer
 
     # TODO: ignore for now (requires more work). Remove ignore once fixed