Fix permalink via parsing for rooms

This adjusts the app local link parsing path to better handle `via`s in query
params. Previously this path only expected them when an event ID was also
present, but it's also valid to have `via`s without event IDs as well.

Fixes https://github.com/vector-im/element-web/issues/16345

test/test-utils.js

@@ -243,6 +243,7 @@ export function mkStubRoom(roomId = null) {
         on: jest.fn(),
         removeListener: jest.fn(),
         getDMInviter: jest.fn(),
+        getAvatarUrl: () => 'mxc://avatar.url/room.png',
     };
 }