Remove redundant messages.

Now that the watcher for `TabbedContent.active` accepts empty strings and emits the message `TabbedContent.Cleared` if `active` is the empty string, we don't need to explicit emit the messages in these two locations.

Author: rodrigogiraoserrao

src/textual/widgets/_tabbed_content.py

@@ -455,8 +455,6 @@ def remove_pane(self, pane_id: str) -> AwaitComplete:
 
         async def _remove_content() -> None:
             await gather(*removal_awaitables)
-            if self.tab_count == 0:
-                self.post_message(self.Cleared(self).set_sender(self))
 
         return AwaitComplete(_remove_content())
 
@@ -474,7 +472,6 @@ def clear_panes(self) -> AwaitComplete:
 
         async def _clear_content() -> None:
             await await_clear
-            self.post_message(self.Cleared(self).set_sender(self))
 
         return AwaitComplete(_clear_content())