Fix T-San Data Race Issues

[stefankiesz]

Issue #, if available:

What was changed?

• Corrected thread synchronization to prevent unsafe access to shared variables across threads.
• Added missing resetting of pConnectionListener->receiveDataRoutine to INVALID_TID_VALUE.
• Fixed RollingBuffer lastIndex race.
• Note: This one only appeared as a T-San warning when I ran the sample myself and connected/disconnected viewer several times - issue did not show when I ran the test suite.

Why was it changed?

• In order to resolve Thread Sanitizer failures.
  • The failures are intermittent on the CI tests - re-running several times will eventually yield passing results.
  • The failures are consistently present when running locally on macOS with LLDB.

How was it changed?

• Added missing mutex locks around asynchronous accessing of variables.
• Set the receiveDataRoutine to INVALID_TID_VALUE whenever THREAD_JOIN is called on its thread. This was done for the IS_VALID_TID_VALUE check to actually be able to check for whether THREAD_JOIN was already called on the thread.
• Wrapped access to pRollingBuffer->lastIndex within the pRollingBuffer->lock.

What testing was done for the changes?

• Ran the test suite locally on Mac with T-San enabled in Debug mode.
• Let the CI to pass 3 times in a row to check for intermittent issues.

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