Fix Settings app ANR due to blocking IDumpstateDevice IPC call

This CL fixes the ANR by moving possible blocking IDumpstateDevice
IPC call from main thread to background thread.

Settings develop options depends on IDumpstateDevice IPC call to
set and get Vendor Verbose Logging feature. The IPC may occasionally
get blocked in system_server which is extremely busy (e.g. during
bugreport generating). This may cause Settings app crashing with ANR.

Bug: 287126040
Bug: 280015761
Test: atest EnableVerboseVendorLoggingPreferenceControllerTest
Test: Verbose Vendor Logging regression
Test: Stress test (heavily trigger on/off during BR generating)
Change-Id: I0b88ef089097930b62dcb1cb7d6fe9990356ab5d