Clip before step

[carmocca]

What does this PR do?

Reorder:

closure
on_before_optimizer_step
optimizer.step
log_grad_norm
clip_gradients

into

closure
on_before_optimizer_step
log_grad_norm
clip_gradients
optimizer.step

Follow-up to #10167

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

None

Before submitting

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• Did you make sure your PR does only one thing, instead of bundling different changes together?
• [n/a] 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?
• [n/a] Did you update the CHANGELOG? This bug is not on any release.

PR review

• Is this pull request ready for review? (if not, please submit in draft mode)
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[codecov]

Codecov Report

Merging #10248 (a151f26) into master (81d15c5) will increase coverage by 4%.
The diff coverage is 86%.

@@           Coverage Diff            @@
##           master   #10248    +/-   ##
========================================
+ Coverage      89%      92%    +4%     
========================================
  Files         180      180            
  Lines       16184    16182     -2     
========================================
+ Hits        14331    14946   +615     
+ Misses       1853     1236   -617     

[tchaton]

LGTM !