cloudv2: Downscale the batch size

[codebien]

The backend has the limit set to 1k so it doesn't make sense to use a bigger value forcing the system to split a single batch in multiple jobs.

We are already overwriting the default value for most of the cases. This PR removes the requirement for setting the env var for doing the overwrite simplifing internal operations.

[codecov-commenter]

Codecov Report

Merging #3193 (3071e74) into master (ac448b0) will increase coverage by 0.02%.
The diff coverage is 100.00%.

❗ Current head 3071e74 differs from pull request most recent head d4479c0. Consider uploading reports for the commit d4479c0 to get more accurate results

@@            Coverage Diff             @@
##           master    #3193      +/-   ##
==========================================
+ Coverage   72.85%   72.87%   +0.02%     
==========================================
  Files         256      256              
  Lines       19803    19804       +1     
==========================================
+ Hits        14428    14433       +5     
+ Misses       4474     4471       -3     
+ Partials      901      900       -1     

Flag	Coverage Δ
ubuntu	72.81% <100.00%> (+0.01%)	⬆️
windows	72.71% <100.00%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
output/cloud/output.go	75.33% <ø> (ø)
cloudapi/config.go	90.90% <100.00%> (ø)
output/cloud/expv2/output.go	65.74% <100.00%> (+0.19%)	⬆️

... and 2 files with indirect coverage changes

[oleiade]

Might be worth adding a comment explaining why we set it too 1000 directly in the code, as you explained here, but not blocking 👍🏻

[codebien]

@oleiade good idea

[codebien]

@olegbespalov added you to make sure you're aware of the change. We don't require anymore to set this option in our operations because the default already matches the requirement.