Update source metadata when latency mode is changed

Keep a cache of source metadata. Use this cache to update source
metadata when latency mode is changed.

Test: mmm packages/modules/Bluetooth
Test: Manual | LE audio streaming with device supporting DSA
Bug: 324953838
Bug: 309665975
Change-Id: If0e5ddb90b09269a8977498b5275a05454fa0fe5