Remove support for Rumble video embeds

src/normalizers/__tests__/status.test.ts

@@ -198,10 +198,4 @@ describe('normalizeStatus()', () => {
     expect(card.type).toEqual('link');
     expect(card.provider_url).toEqual('https://soapbox.pub');
   });
-
-  it('preserves Truth Social external_video_id', () => {
-    const status = require('soapbox/__fixtures__/truthsocial-status-with-external-video.json');
-    const result = normalizeStatus(status);
-    expect(result.media_attachments.get(0)?.external_video_id).toBe('vwfnq9');
-  });
 });

src/normalizers/attachment.ts

@@ -15,7 +15,6 @@ import { mergeDefined } from 'soapbox/utils/normalizers';
 export const AttachmentRecord = ImmutableRecord({
   blurhash: undefined,
   description: '',
-  external_video_id: null as string | null, // TruthSocial
   id: '',
   meta: ImmutableMap(),
   pleroma: ImmutableMap(),