Remove check num_slurm_tasks in Lite

[awaelchli]

What does this PR do?

Follow up to #14300 for Lite's Connector.
Resolves the corresponding TODO in the code.

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Did you have fun?

I made sure I had fun coding 🙃

cc @Borda @justusschock @awaelchli @rohitgr7 @tchaton @carmocca

[codecov]

Codecov Report

Merging #14761 (df8240b) into master (35c65b0) will increase coverage by 1%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master   #14761     +/-   ##
=========================================
+ Coverage      84%      85%     +1%     
=========================================
  Files         395      276    -119     
  Lines       28805    21120   -7685     
=========================================
- Hits        24087    17972   -6115     
+ Misses       4718     3148   -1570