test(base): Fix an incorrect data for a test.

This patch fixes a test data: it uses `r0` to create an event for room
`r1`. This doesn't change the test but the data was wrong.

crates/matrix-sdk-base/src/event_cache/store/integration_tests.rs

@@ -1286,7 +1286,7 @@ impl EventCacheStoreIntegrationTests for DynEventCacheStore {
                 // new items on 0
                 Update::PushItems {
                     at: Position::new(CId::new(2), 0),
-                    items: vec![make_test_event(r0, "yummy")],
+                    items: vec![make_test_event(r1, "yummy")],
                 },
             ],
         )