Ruff: Add and fix RUF015

[kiblik]

Originally proposed in #10712 but I didn't like Ruff's autofix

This PR is trying to address unnecessary-iterable-allocation-for-first-element (RUF015)

next(iter(x)) is proposed by Ruff but it is a bit hard to read it in code so I wrote a wrapper.
Plus, I dropped som conversions to a list where it is not needed.

[dryrunsecurity]

DryRun Security Summary

The pull request implements code refactoring by introducing a first_elem() utility function while revealing minor security concerns in the Cobalt API client's handling of credentials and error messages, though no critical vulnerabilities were introduced.

Expand for full summary

The pull request introduces minor refactoring across multiple files, consistently replacing list(x.keys())[0] or list(x.values())[0] with a new utility function first_elem() from dojo.utils. Security findings include potential information exposure in API client error handling and API token management in the Cobalt API client, with no critical vulnerabilities introduced by the code changes.

Specific security observations:

1. In dojo/tools/api_cobalt/api_client.py:
   • API credentials passed directly in headers
   • Full API response content logged in exceptions
   • Single authentication method (API key)
   • Potential information exposure in error messages

No other significant security vulnerabilities were identified across the modified files.

Code Analysis

We ran 9 analyzers against 16 files and 0 analyzers had findings. 9 analyzers had no findings.

View PR in the DryRun Dashboard.

[Maffooch]

Hey @kiblik I am super conflicted about this one, but have not landed on a stance I feel great about.

On one hand, I like the approach of abstracting away next(iter(x)) as it does not appear all that intuitive at first glance. On the other hand, this takes away the opportunity to learn why the use of the iterator is the safer and performant approach. I don't have much experience in iterators in python, and learned something very valuable from just this PR 😄

I have no qualms with the ruff rule introduced here, but am on the fence about the use of the utility (we have a ton of those as it is 😅 )