AutoOn: Clear stored timer when bluetooth is on

Timer is obsolete when bluetooth reach state on. Deleting the storage
prevent miss-activation of the feature

Bug: 323060869
Bug: 333353069
Fix: 333353069
Flag: com.android.bluetooth.flags.auto_on_feature
Test: atest ServiceBluetoothRoboTest
Change-Id: I4bffa7527f81cbc82031eb41eb05720206a7bd67