Deprecate lr_sch_names from LearningRateMonitor

[rohitgr7]

What does this PR do?

See title

Does your PR introduce any breaking changes? If yes, please list them.

Before submitting

• Was this discussed/approved via a GitHub issue? (not for typos and docs)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure your PR does only one thing, instead of bundling different changes together?
• Did you make sure to update the documentation with your changes? (if necessary)
• Did you write any new necessary tests? (not for typos and docs)
• Did you verify new and existing tests pass locally with your changes?
• Did you list all the breaking changes introduced by this pull request?
• Did you update the CHANGELOG? (not for typos, docs, test updates, or internal minor changes/refactorings)

PR review

Anyone in the community is welcome to review the PR.
Before you start reviewing make sure you have read Review guidelines. In short, see the following bullet-list:

• Is this pull request ready for review? (if not, please submit in draft mode)
• Check that all items from Before submitting are resolved
• Make sure the title is self-explanatory and the description concisely explains the PR
• Add labels and milestones (and optionally projects) to the PR so it can be classified

Did you have fun?

Make sure you had fun coding 🙃

[github-actions]

Build Error! No Linked Issue found. Please link an issue or mention it in the body using #<issue_id>

[codecov]

Codecov Report

Merging #10066 (c302980) into master (dbe1662) will increase coverage by 4%.
The diff coverage is 100%.

❗ Current head c302980 differs from pull request most recent head a565893. Consider uploading reports for the commit a565893 to get more accurate results

@@            Coverage Diff            @@
##           master   #10066     +/-   ##
=========================================
+ Coverage      89%      93%     +4%     
=========================================
  Files         180      182      +2     
  Lines       16146    16944    +798     
=========================================
+ Hits        14317    15745   +1428     
+ Misses       1829     1199    -630