Add nicer error message when init fails

[frode-aarstad]

Issue
Resolves #9466

Approach
To test.

pip install ropt==0.4.3
everest run test-data/everest/math_func/config_advanced.yml

Should get a error message not a stacktrace

• 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

[codspeed-hq]

CodSpeed Performance Report

Merging #9653 will not alter performance

_{Comparing frode-aarstad:try-init (decfdfd) with main (7d73f74)}

Summary

✅ 24 untouched benchmarks

[verveerpj]

LGTM!

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 33.33333% with 4 lines in your changes missing coverage. Please review.

Project coverage is 91.70%. Comparing base (7d73f74) to head (decfdfd).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/everest/__init__.py	33.33%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9653      +/-   ##
==========================================
- Coverage   91.71%   91.70%   -0.02%     
==========================================
  Files         430      430              
  Lines       26639    26644       +5     
==========================================
+ Hits        24433    24434       +1     
- Misses       2206     2210       +4     

Flag	Coverage Δ
cli-tests	39.69% <ø> (ø)
everest-models-test	34.18% <ø> (-0.02%)	⬇️
gui-tests	71.83% <ø> (ø)
integration-test	38.30% <ø> (ø)
performance-tests	51.78% <ø> (+0.09%)	⬆️
test	39.62% <ø> (+0.01%)	⬆️
unit-tests	73.98% <33.33%> (-0.02%)	⬇️

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