e2e: Fix false-positive in canonical ref update test

Previously `test_fetch_emits_canonical_ref_update` was passing by
catching a leftover `CanonicalRefUpdated` event from the initial
repository fetch. Furthermore, the new commit was written to the
un-namespaced root. It can be proven to be the case by commenting out
the `alice.commit_to(...)` line and watching the test still pass.

Fix the test by committing to the namespaced default branch which will
trigger the `CanonicalRefUpdated` that is expected by Bob. Drains events
so we don't catch the wrong event, and explicitly announces.

crates/radicle-node/src/tests/e2e.rs

@@ -1691,13 +1691,20 @@ fn test_fetch_emits_canonical_ref_update() {
         .unwrap();
     assert!(result.is_success());
 
+    // Drain all the events including initial `CanonicalRefUpdated`
+    // from fetch
+    while bob_events.try_recv().is_ok() {}
+
     let default_branch: git::fmt::Qualified = {
         let repo = alice.storage.repository(rid).unwrap();
         let proj = repo.project().unwrap();
         git::fmt::lit::refs_heads(proj.default_branch()).into()
     };
+
     alice.commit_to(rid, &default_branch);
 
+    alice.handle.announce_refs_for(rid, [alice.id]).unwrap();
+
     bob_events
         .wait(
             |e| {