Fixes incorrect strategy init with HPUAccelerator

[ankitgola005]

What does this PR do?

Fixes for incorrect strategy init with HPUAccelerator
Accelerator_connector only picks correct "auto" strategy when accelerator is set as "hpu". setting it with class instance fails this check and it sets default strategy from SingleDeviceStrategy / DDPStrategy instead of SingleHPUStrategy / ParallelHPUStrategy.

Fixes #19614

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📚 Documentation preview 📚: https://pytorch-lightning--19615.org.readthedocs.build/en/19615/

[awaelchli]

Thanks!

[codecov]

Codecov Report

Merging #19615 (0ef76eb) into master (096b063) will decrease coverage by 31%.
Report is 4 commits behind head on master.
The diff coverage is 90%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #19615      +/-   ##
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- Coverage      84%      53%     -31%     
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  Files         424      416       -8     
  Lines       34903    34752     -151     
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- Hits        29347    18435   -10912     
- Misses       5556    16317   +10761