[MM-62587] Hide thread_footer when root post is deleted (#29874)

* [MM-62587] Hide thread_footer when root post is deleted

* Also remove the replies line from the RHS

* Fix logic to make sure post.delete_at exists

* Fix playwright test

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Co-authored-by: Mattermost Build <build@mattermost.com>

e2e-tests/playwright/tests/functional/channels/drafts/drafts_on_deleted_message.spec.ts

@@ -62,7 +62,7 @@ test('MM-T5435_1 Global Drafts link in sidebar should be hidden when another use
     }
 
     // # Open the last post in the channel sent by admin again
-    await lastPostByAdmin.threadFooter.reply();
+    await lastPostByAdmin.body.click();
 
     // * Verify drafts in user's textbox is still visible
     const rhsTextboxValue = await sidebarRight.postCreate.getInputValue();