ETW trace logger is fakely registered as initialized_ is marked as true
before the registration is done, causing crashing issue for Lenovo
camera application.

A prior attempt to address was made here:
#21226
It was reverted here:
#21360

The problem is that during initialization of TraceLoggingRegisterEx, it
will reinvoke the callback and attempt reinitialization, which is not
allowed. TraceLoggingRegisterEx however can be initialized concurrently
when initialization happens on multiple threads. For these reasons it
needs to be protected by a lock, but the lock cannot naively block
because the callback's reinvocation will cause a deadlock.

To solve this problem another tracking variable is added :
"initializing" which protects against reinitialization during the first
initialization.

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Co-authored-by: Sheil Kumar <[email protected]>