Fix a bug where turning off Bluetooth before CDM BLE device discovery timeout results in a crash.

Bug: 427498880
Test: Manual test on CompanionDeviceTestApp (replaced with BLE scan)
Flag: EXEMPT bug fix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:bb7eeb8a82746df453906afcbbb9389f2980136a)
Merged-In: I48efc1279f7406b141d60d3931c7b61116c5c0f3
Change-Id: I48efc1279f7406b141d60d3931c7b61116c5c0f3