feat: add e2e tests

[35C4n0r]

Closes #3053

📑 Description

✅ Checks

• My pull request adheres to the code style of this project
• My code requires changes to the documentation
• I have updated the documentation as required
• All the tests have passed

ℹ Additional Information

[vercel]

@35C4n0r is attempting to deploy a commit to the KeepHQ Team on Vercel.

A member of the Team first needs to authorize it.

[gitguardian]

️✅ There are no secrets present in this pull request anymore.

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[codecov]

Codecov Report

Attention: Patch coverage is 31.37255% with 105 lines in your changes missing coverage. Please review.

Project coverage is 31.31%. Comparing base (e8cbcb3) to head (755350a).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
tests/e2e_tests/test_grafana_provider.py	29.80%	73 Missing ⚠️
tests/e2e_tests/test_end_to_end.py	27.90%	31 Missing ⚠️
tests/e2e_tests/test_pushing_prometheus_alerts.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #3054       +/-   ##
===========================================
- Coverage   43.06%   31.31%   -11.76%     
===========================================
  Files         166       74       -92     
  Lines       16685     8184     -8501     
===========================================
- Hits         7186     2563     -4623     
+ Misses       9499     5621     -3878     

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