Fetch homeUrl from .well-known (#7790)

* Fetch homeUrl from .well-known

* homeUrl: prefer config.json over .well-known

* homeUrl: prefer deprecated config.json variant over .well-known

* Apply suggestions from code review

Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>

Co-authored-by: Michael Telatynski <7t3chguy@gmail.com>
Co-authored-by: Travis Ralston <travisr@matrix.org>

src/utils/pages.ts

@@ -17,6 +17,7 @@ limitations under the License.
 import { logger } from "matrix-js-sdk/src/logger";
 
 import { IConfigOptions } from "../IConfigOptions";
+import { getEmbeddedPagesWellKnown } from '../utils/WellKnownUtils';
 import { SnakedObject } from "./SnakedObject";
 
 export function getHomePageUrl(appConfig: IConfigOptions): string | null {
@@ -38,6 +39,10 @@ export function getHomePageUrl(appConfig: IConfigOptions): string | null {
         }
     }
 
+    if (!pageUrl) {
+        pageUrl = getEmbeddedPagesWellKnown()?.home_url;
+    }
+
     return pageUrl;
 }