[Coverity][UR] Potential double-unlock of a mutex in the L0 adapter

Reported by Coverity as CID `520793`, you can access Coverity results here: https://scan.coverity.com/projects/intel-llvm?tab=overview

The following piece of code:

https://github.com/intel/llvm/blob/faa61805224a993f8f9de6214ba0678afc9e53e4/unified-runtime/source/adapters/level_zero/event.cpp#L1585-L1588

Is located within a loop:

https://github.com/intel/llvm/blob/faa61805224a993f8f9de6214ba0678afc9e53e4/unified-runtime/source/adapters/level_zero/event.cpp#L1552-L1553

Meaning, that we may call `CurQueue->Mutex.unlock();` multiple times. That mutex is a [`std::shared_mutex`](https://en.cppreference.com/w/cpp/thread/shared_mutex.html) whose [`unlock`](https://en.cppreference.com/w/cpp/thread/shared_mutex/unlock.html) method behavior is undefined if a mutex is already unlocked.