Conform more code to strictNullChecks (#10444

* Conform more code to `strictNullChecks`

* Fix tests

* Fix tests

src/hooks/usePermalinkEvent.ts

@@ -75,8 +75,8 @@ export const usePermalinkEvent = (
         const fetchRoomEvent = async (): Promise<void> => {
             try {
                 const eventData = await MatrixClientPeg.get().fetchRoomEvent(
-                    parseResult.roomIdOrAlias,
-                    parseResult.eventId,
+                    parseResult.roomIdOrAlias!,
+                    parseResult.eventId!,
                 );
                 setEvent(new MatrixEvent(eventData));
             } catch {}

src/hooks/usePermalinkTargetRoom.ts

@@ -83,7 +83,7 @@ const findRoom = (roomIdOrAlias: string): Room | null => {
 export const usePermalinkTargetRoom = (
     type: PillType | null,
     parseResult: PermalinkParts | null,
-    permalinkRoom: Room | null,
+    permalinkRoom: Room | undefined,
 ): Room | null => {
     // The listed permalink types require a room.
     // If it cannot be initially determined, it will be looked up later by a memo hook.