[12.x] Enhance Broadcast Events Test Coverage

[roshandelpoor]

This PR adds test coverage for custom broadcasting configurations, focusing on multiple channels, custom connections, event names, and payload handling.

Added Test Cases

• testBroadcastWithMultipleChannels
  • Verifies broadcasting to multiple channels simultaneously
  • Tests handling of ['channel-1', 'channel-2'] configuration
• testBroadcastWithCustomConnectionName
  • Tests broadcasting with custom connection name
  • Ensures custom connection property is properly handled
• testBroadcastWithCustomEventName
  • Validates custom event name broadcasting via broadcastAs()
  • Ensures event name customization works as expected
• testBroadcastWithCustomPayload
  • Tests custom payload broadcasting via broadcastWith()
  • Verifies custom data handling in broadcast payloads

Why

These test cases ensure that the broadcasting system correctly handles:

• Multiple channel broadcasting scenarios
• Custom connection configurations
• Event name customization
• Custom payload data