ci: use shared python_package_check workflow from apify/workflows

Replaces the local _check_package.yaml with a direct call to the
shared reusable workflow.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: vdusek

.github/workflows/_check_package.yaml

@@ -19,7 +19,10 @@ jobs:
 
   package_check:
     name: Package check
-    uses: ./.github/workflows/_check_package.yaml
+    uses: apify/workflows/.github/workflows/python_package_check.yaml@main
+    with:
+      package_name: apify_shared
+      src_package_dir: src/apify_shared
 
   tests:
     name: Tests