fix: validation (better #8456) (#8461)

* Revert "revert 484e023c0"

This reverts commit c03b70c949.

* also allow pure renote

* fix checks for pure renote

packages/backend/src/server/api/endpoints/notes/global-timeline.ts

@@ -35,7 +35,11 @@ export const meta = {
 export const paramDef = {
 	type: 'object',
 	properties: {
-		withFiles: { type: 'boolean' },
+		withFiles: {
+			type: 'boolean',
+			default: false,
+			description: 'Only show notes that have attached files.',
+		},
 		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
 		sinceId: { type: 'string', format: 'misskey:id' },
 		untilId: { type: 'string', format: 'misskey:id' },