[PBE-3941] Fix event deserialization issues

[liviu-timar]

🎯 Goal

Deserialization error is printed in the logs multiple times when a received event could not be mapped with one of our classes. The CoordinatorSocket.onMessage() deserialization logic needs to be refactored.

Patreon Zendesk ticket here.

🛠 Implementation details

• Added UnsupportedVideoEventException to separately handle the "cannot map with class" case.
• Added handling for ConnectionErrorEvent and removed SocketError handling. We never get a message that can be mapped to SocketError with field error. ❓
• Added transcription event classes.

🧪 Testing

• Check CoordinatorSocket.onMessage().
• Run app and follow logs.
• Check OpenAPI specs to confirm that trying to map to SocketError is not good.

☑️Contributor Checklist

General

• I have signed the Stream CLA (required)
• Assigned a person / code owner group (required)
• Thread with the PR link started in a respective Slack channel (required internally)
• PR targets the develop branch
• PR is linked to the GitHub issue it resolves

☑️Reviewer Checklist

• XML sample runs & works
• Compose sample runs & works
• Tutorial starter kit
• Example starter kits work
• UI Changes correct (before & after images)
• Bugs validated (bugfixes)
• New feature tested and works
• Release notes and docs clearly describe changes
• All code we touched has new or updated KDocs

[aleksandar-apostolov]

Resolve merge conflicts before merging, otherwise OK