[BUG] Extract magic number 100 to named constant

[cachebag]

Describe the bug
State 100 (Activated) is used as a magic number in monitoring/bluetooth.rs lines 68, 112. Should use device_state::ACTIVATED from constants.

[AK78gz]

Hi! I’d like to work on this issue.
Could you please assign it to me?

[cachebag]

@AK78gz Thanks. Please ensure you read the contributing guidelines