Fix Tuner CTS test deadlock issue

When closing filter, the lock order will be FilterClient::mLock and then
TunerFilter::FilterCallback::mCallbackLock. The onFilterEvent callback
lock order is TunerFilter::FilterCallback::mCallbackLock and then
FilterClient::mLock when releasing av handle. Thus the deadlock can happen
when an application try to release av handle while closing the filter.

The solution is to release the lock after copy the callback pointer to a
local variable to release the callback lock when deliver events back to
java layer by onFilterEvent.

Flag: TEST_ONLY
Bug: 369726603
Test: atest android.media.tv.tuner.cts.TunerTest --iteration 10
Change-Id: I517d7ab50c9156c315431e58a7e6886b5d42b765