Fix warning for Dataloader if num_workers = cpu count = 1

[dipta007]

What does this PR do?

This PR checks if the num_workers of dataloader should be more than the assigned.
Previously even if the available num_worker was 1 and the value in the dataloader was given 1, there was a warning stating to give num_worker=1, which is wrong.

Fixes #19223

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• Did you write any new necessary tests? (not for typos and docs) - No
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• Did you list all the breaking changes introduced by this pull request? - Yes
• Did you update the CHANGELOG? (not for typos, docs, test updates, or minor internal changes/refactors) - No

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📚 Documentation preview 📚: https://pytorch-lightning--19224.org.readthedocs.build/en/19224/

[codecov]

Codecov Report

Merging #19224 (75f83c7) into master (4d6acda) will decrease coverage by 34%.
The diff coverage is 100%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #19224      +/-   ##
==========================================
- Coverage      83%      49%     -34%     
==========================================
  Files         445      437       -8     
  Lines       37301    37148     -153     
==========================================
- Hits        31002    18238   -12764     
- Misses       6299    18910   +12611     

[dipta007]

@awaelchli @carmocca any update here?
I think one of the tests has been failed due to timeout.
I tried to restart it but I think I dont have the permission to do so.

[awaelchli]

@dipta007 We will merge the PR as soon as we fix the failing docs build. Thanks for your understanding.