Patterns: Fix empty general template parts category (#52747)

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Co-authored-by: Glen Davies <[email protected]>

packages/edit-site/src/components/page-patterns/patterns-list.js

@@ -27,7 +27,7 @@ import usePatterns from './use-patterns';
 import SidebarButton from '../sidebar-button';
 import useDebouncedInput from '../../utils/use-debounced-input';
 import { unlock } from '../../lock-unlock';
-import { SYNC_TYPES, USER_PATTERN_CATEGORY } from './utils';
+import { SYNC_TYPES, USER_PATTERN_CATEGORY, PATTERNS } from './utils';
 
 const { useLocation, useHistory } = unlock( routerPrivateApis );
 
@@ -58,9 +58,12 @@ export default function PatternsList( { categoryId, type } ) {
 	const [ syncFilter, setSyncFilter ] = useState( 'all' );
 	const deferredSyncedFilter = useDeferredValue( syncFilter );
 
+	const isUncategorizedThemePatterns =
+		type === PATTERNS && categoryId === 'uncategorized';
+
 	const { patterns, isResolving } = usePatterns(
 		type,
-		categoryId !== 'uncategorized' ? categoryId : '',
+		isUncategorizedThemePatterns ? '' : categoryId,
 		{
 			search: deferredFilterValue,
 			syncStatus: