Floss: suspend and resume discovery

This patch handles the system suspend and resume for classic discovery.
- It pauses the discovery when the system is suspending.
- It resumes the discovery when the system is resuming.
- It prevent APIs from re-enabling by returning the busy status.

Bug: 269683410
Tag: #floss
BYPASS_LONG_LINES_REASON: Bluetooth likes 120 lines
Test: passed bluetooth_AdapterSRHealth.sr_while_discovering.floss

Change-Id: I4a8880312d3229982363a1ca3ff8c8664496ea1d