Delete the remainder of groups (#9357)

* Delete the remainder of groups

Fixes https://github.com/vector-im/element-web/issues/22770
Continues https://github.com/matrix-org/matrix-react-sdk/pull/8027

* Don't need the strings either

src/IConfigOptions.ts

@@ -179,9 +179,6 @@ export interface IConfigOptions {
 
     sync_timeline_limit?: number;
     dangerously_allow_unsafe_and_insecure_passwords?: boolean; // developer option
-
-    // XXX: Undocumented URL for the "Learn more about spaces" link in the "Communities don't exist" messaging.
-    spaces_learn_more_url?: string;
 }
 
 export interface ISsoRedirectOptions {