Support for Flickr album and group pool embeds (#3936)

* Support for Flickr album and group pool embeds

* Oops, forgot to add flickr to the persisted externalEmbeds schema

* Need a bigint since our id can have more than 52 bits...

* Remove unexpected trailing / from test data to match the expected behavior

* nits

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Co-authored-by: Hailey <me@haileyok.com>

src/state/persisted/schema.ts

@@ -65,6 +65,7 @@ export const schema = z.object({
       spotify: z.enum(externalEmbedOptions).optional(),
       appleMusic: z.enum(externalEmbedOptions).optional(),
       soundcloud: z.enum(externalEmbedOptions).optional(),
+      flickr: z.enum(externalEmbedOptions).optional(),
     })
     .optional(),
   mutedThreads: z.array(z.string()), // should move to server