Merge changes from topic "cherrypicker-L22800030000756195:N75200030012855151" into main
* changes:
[nearby] Add nearby_enable_ble_in_init flag
Revert "[nearby] Add disable logic"
[nearby] Add disable logic
[nearby] Log changes
[nearby] Sync discoveryTimestamp field name
[nearby] Enable BLE when init
[nearby] Add logs to broadcaster
[nearby] Add discoveryTimestamp field
[nearby] Fix flakeness in the unit test
[nearby][clean up] Remove useless legacy code
[nearby] Fix the user-debug only test
[nearby] Catches NPE in ChreDiscoveryProvider
[nearby] Update README to add build env script