Allow the forced scan mode to be lower one during screen off

- After scan timeout, scan mode is set to low power scan mode
- The forced mode is alowed up to low power scan mode
- The forced scan mode could also be screen off scan mode

Bug: 289580163
Bug: 296909825
Test: atest BluetoothInstrumentationTests and device test
Change-Id: I762f0be9f8597b6835671abe2c346481b314932c