e2e: fix resume/full-reconnect. (#194)

* fix: full re-connect.

* chore: Reset fullReConnect state after ConnectionState is emitted.

* Support full reconnect, fix Migration, NodeFailure, FullReconnect test cases.

* revert Timeouts.connection.

* update.

* Refactor the resume/reconnect implementation.

* more changes.

* update.

* Changed to simpler reconnect/recovery logic.

* update.

* update.

* code format.

* tidy.

* bump version for flutter-webrtc.

* chore: Remove unused exception class (SignalReconnectError).

* chore: rename `fullReconnectOnNext` to `fullReconnect`.

* update.

* chore: Revert changes for `unpublishTrack`.

* chore: Reconnect signalClient when resumeConnection.

* revert `rethrow` in engine.connect.

* Use removePublishedTrack instead of unpublishTrack (RemoteParticipant).

* chore: Correctly handle PeerConnectionState for resume/full-reconnect.

* tidy.

lib/src/exceptions.dart

@@ -23,6 +23,11 @@ class UnexpectedStateException extends LiveKitException {
       : super._(msg);
 }
 
+/// Exception thrown when pc negotiation fails.
+class NegotiationError extends LiveKitException {
+  NegotiationError([String msg = 'Negotiation Error']) : super._(msg);
+}
+
 /// Failed to create a local track.
 /// Common reasons:
 /// - Required permissions not yet granted to the platform.