Diagnostics for duplicate participant matches and mid-delivery scope teardown

Warn when ConnectionManagerData merges participants from a second
connection to the same SFU URL, when more than one LiveKit participant
matches a member's backend identity, and when a scope is ended while one
of its behaviors is still delivering a value (which strands the later
bound subscribers on the old value). The per-member match log now also
names the connection the participant came from.

src/state/CallViewModel/remoteMembers/MatrixLivekitMembers.test.ts

@@ -111,7 +111,7 @@ test("should signal participant not yet connected to livekit", async () => {
     },
   );
   expect(info).toHaveBeenCalledWith(
-    "[RemoteMatrixLivekitMembers] @bob:example.org:DEV000: LiveKit participant missing",
+    "[RemoteMatrixLivekitMembers] @bob:example.org:DEV000: LiveKit participant missing on no connection",
   );
 });