Don't copy the parent block of TaskIncludes when loading statically

When loading an include statically, we previously were simply doing a
copy() of the TaskInclude object, which recurses up the parents creating
a new lineage of objects. This caused problems when used inside load_list_of_blocks
as the new parent Block of the new TaskInclude was not actually in the list
of blocks being operated on. In most circumstances, this did not cause a
problem as the new parent block was a proper copy, however when used in
combination with PlaybookInclude (which copies conditionals to the list of
blocks loaded) this untracked parent was not being properly updated, leading
to tasks being run improperly.

Fixes #18206

lib/ansible/playbook/conditional.py

@@ -51,6 +51,17 @@ class Conditional:
         if not isinstance(value, list):
             setattr(self, name, [ value ])
 
+    def _get_attr_when(self):
+        '''
+        Override for the 'tags' getattr fetcher, used from Base.
+        '''
+        when = self._attributes['when']
+        if when is None:
+            when = []
+        if hasattr(self, '_get_parent_attribute'):
+            when = self._get_parent_attribute('when', extend=True)
+        return when
+
     def evaluate_conditional(self, templar, all_vars):
         '''
         Loops through the conditionals set on this object, returning