[CI] Re-enable transcriptions test_long_audio_request

[NickLucche]

This is a cruft from Voxtral integration, this test is supposed to run (and pass) on whisper, but not on Voxtral.
Thanks to @mgoin for reporting.

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[gemini-code-assist]

Code Review

This pull request correctly re-enables the test_long_audio_request test for Whisper models by removing a conditional statement that was causing it to be skipped. The change is sound and aligns with the stated intent to have this test run for Whisper models.