MM-25007: Add staticcheck (#14522)

app/file.go

@@ -330,8 +330,7 @@ func (a *App) MigrateFilenamesToFileInfos(post *model.Post) []*model.FileInfo {
 	}
 
 	// Copy and save the updated post
-	newPost := &model.Post{}
-	newPost = post.Clone()
+	newPost := post.Clone()
 
 	newPost.Filenames = []string{}
 	newPost.FileIds = fileIds