[QNN EP] Fix multithread sync bug in ETW callback

[adrianlizarraga]

Description

Fixes crash in QNN dlls when an ETW callback tries to change the QNN log level. This is caused by a function that does not lock a mutex before modifying the QNN log level.

Motivation and Context

An ETW callback into QNN EP leads to a crash within QNN SDK dlls. It happens 1 out of 3 full QNN unit tests runs.

The cause is a multithreading synchronization bug in QNN EP. We're not always locking a mutex when ETW calls QNN EP to notify of ETW config change.

There are two branches in the QNN EP callback function that try to update the QNN log handle. One branch correctly locks a mutex, but other does not lock it at all. This causes crashes within QNN dlls.

• Does not lock mutex: onnxruntime/onnxruntime/core/providers/qnn/qnn_execution_provider.cc at main · microsoft/onnxruntime
• Locks mutex: onnxruntime/onnxruntime/core/providers/qnn/qnn_execution_provider.cc at main · microsoft/onnxruntime

The fix is to lock the mutex in both paths.

[adrianlizarraga]

Note: This is the root of the problem. The UpdateQnnLogLevel function was not locking a mutex.

I combined UpdateQnnLogLevel() and ResetQnnLogLevel() into a single function that locks the mutex and handles both updating and resetting.