Catch import warnings in a common location for both get() and all()

Potential solution for #12979

lib/ansible/plugins/__init__.py

@@ -307,6 +307,8 @@ class PluginLoader:
         if name in sys.modules:
             # See https://github.com/ansible/ansible/issues/13110
             return sys.modules[name]
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", RuntimeWarning)
             with open(path, 'r') as module_file:
                 module = imp.load_source(name, path, module_file)
         return module
@@ -344,8 +346,6 @@ class PluginLoader:
                     continue
 
                 if path not in self._module_cache:
-                    with warnings.catch_warnings():
-                        warnings.simplefilter("ignore", RuntimeWarning)
                     self._module_cache[path] = self._load_module_source(name, path)
 
                 if kwargs.get('class_only', False):