[GH-25484] Fix draft removal on post deletion (#25715)

* [GH-25484] Fix draft removal on post deletion

* [GH-25484] Add batch migration to remove orphan drafts

* [GH-25484] Fix tests of migration and draft store

* [GH-25484] Remove translation file changes.

* [GH-25484] Remove translation file changes.

---------

Co-authored-by: Devin Binnie <52460000+devinbinnie@users.noreply.github.com>
Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Harrison Healey <harrisonmhealey@gmail.com>

server/channels/app/post.go

@@ -1417,11 +1417,23 @@ func (a *App) DeletePost(c request.CTX, postID, deleteByID string) (*model.Post,
 		}
 	})
 
+	// delete drafts associated with the post when deleting the post
+	a.Srv().Go(func() {
+		a.deleteDraftsAssociatedWithPost(c, channel, post)
+	})
+
 	a.invalidateCacheForChannelPosts(post.ChannelId)
 
 	return post, nil
 }
 
+func (a *App) deleteDraftsAssociatedWithPost(c request.CTX, channel *model.Channel, post *model.Post) {
+	if err := a.Srv().Store().Draft().DeleteDraftsAssociatedWithPost(channel.Id, post.Id); err != nil {
+		c.Logger().Error("Failed to delete drafts associated with post when deleting post", mlog.Err(err))
+		return
+	}
+}
+
 func (a *App) deleteFlaggedPosts(c request.CTX, postID string) {
 	if err := a.Srv().Store().Preference().DeleteCategoryAndName(model.PreferenceCategoryFlaggedPost, postID); err != nil {
 		c.Logger().Warn("Unable to delete flagged post preference when deleting post.", mlog.Err(err))