Local participant's identity not sent with RPC request

[ladvoc]

Describe the bug
When performing an RPC call using Room.performRpc(destinationIdentity:method:payload:responseTimeout:), the identity of the local participant is not set on the outgoing data packet encapsulating the RPC request.

SDK Version
2.1.0

iOS/macOS Version
macOS 15.3.1

Xcode Version
16.2

Steps to Reproduce

1. Perform an RPC call.
2. Inspect the participantIdentity field on the outgoing data packet; this should be set to the local participant's identity, but is currently an empty string.

This can be verified in RpcTests.testPerformRpc().