bridge_simple: Improve renegotiation success rate.

bridge_simple: Improve renegotiation success rate.

When making channels compatible the bridge_simple module
will renegotiate one to better match the other. Some
endpoints incorrectly terminate the call if this process
fails.

To better handle this scenario the audio streams present
on the new requested topology will include any existing
negotiated formats that happen to exist on the first
valid audio stream. This ensures formats are persent that
are known to be acceptable to the remote endpoint.

ASTERISK-27259

Change-Id: I8fc0cc03e8bcfd0be8302f13b9f32d8268977f43