Remove X_local from global update

[dafeda]

Do in-place matrix multiplaction

Issue Resolves #my_issue

Approach Short description of the approach

(Screenshot of new behavior in GUI if applicable)

Pre review checklist

• [ ] Read through the code changes carefully after finishing work
• [ ] Make sure tests pass locally (after every commit!)
• [ ] Prepare changes in small commits for more convenient review (optional)
• [ ] PR title captures the intent of the changes, and is fitting for release notes.
• [ ] Updated documentation
• [ ] Ensured that unit tests are added for all new behavior (See Ground Rules), and changes to existing code have good test coverage.

Pre merge checklist

• [ ] Added appropriate release note label
• [ ] Commit history is consistent and clean, in line with the contribution guidelines.

[codecov-commenter]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (f30d83a) 83.88% compared to head (f257586) 83.88%. Report is 1 commits behind head on main.

Files	Patch %	Lines
src/ert/analysis/_es_update.py	94.44%	2 Missing :warning:

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6818   +/-   ##
=======================================
  Coverage   83.88%   83.88%           
=======================================
  Files         365      365           
  Lines       21444    21449    +5     
  Branches      948      948           
=======================================
+ Hits        17988    17993    +5     
  Misses       3162     3162           
  Partials      294      294           

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