Remove checks for storage_server.json in storage

[JHolba]

We no longer use this file for connection info.
Seems to be leftovers from earlier code.

Issue
Resolves #8452

Approach
remove all use of storage_server.json

• PR title captures the intent of the changes, and is fitting for release notes.
• Added appropriate release note label
• Commit history is consistent and clean, in line with the contribution guidelines.
• Make sure unit tests pass locally after every commit (git rebase -i main --exec 'pytest tests/ert/unit_tests -n logical -m "not integration_test"')

When applicable

• When there are user facing changes: Updated documentation
• New behavior or changes to existing untested code: Ensured that unit tests are added (See Ground Rules).
• Large PR: Prepare changes in small commits for more convenient review
• Bug fix: Add regression test for the bug
• Bug fix: Create Backport PR to latest release

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.80%. Comparing base (b9cfd46) to head (fccf325).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8939      +/-   ##
==========================================
+ Coverage   91.65%   91.80%   +0.14%     
==========================================
  Files         343      343              
  Lines       21149    21201      +52     
==========================================
+ Hits        19385    19463      +78     
+ Misses       1764     1738      -26     

Flag	Coverage Δ
cli-tests	39.81% <100.00%> (-0.02%)	⬇️
gui-tests	73.73% <100.00%> (-0.12%)	⬇️
performance-tests	50.40% <100.00%> (-0.05%)	⬇️
unit-tests	80.45% <100.00%> (+0.18%)	⬆️

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[xjules]

Nice! ✂️