[XLA:Python] Factors the ":logging" library out from ":xla_extension".
[XLA:Python] Factors the ":logging" library out from ":xla_extension".

This is a prospective change for https://github.com/openxla/xla/pull/10966.  In particular, this will help fix an OSS build problem: "tensorflow/xla/linux/cpu/build_cpu" not being able to find the `InitializeAbslLogging` function.
