Update clean_podcast_url() in _utils.py

[mabdelfattah]

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Description of your pull request and other information

Fix for #7430 and #7544
Example URLs:
https://pdst.fm/e/2.gum.fm/chtbl.com/track/chrt.fm/track/34D33/pscrb.fm/rss/p/traffic.megaphone.fm/ITLLC7765286967.mp3?updated=1687282661

https://pdst.fm/e/https://mgln.ai/e/441/www.buzzsprout.com/1121972/13019085-ep-252-the-deep-life-stack.mp3

Template

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Copilot Summary

🤖 Generated by Copilot at 436c63c

Summary

🐛🧹🎧

Fix and improve podcast URL cleaning in yt_dlp/utils/_utils.py. Use regex to avoid adding extra http:// or https:// to podcast URLs.

clean_podcast_url is the function of doom
It strips away the noise and the gloom
With a regex group it slays the duplicates
No more protocol prefixes to confuse and frustrate

Walkthrough

• Fix duplicate protocol prefix bug in podcast URLs by capturing and reusing the first prefix in a regex group (link)
• Remove redundant line of code that was doing the same thing as the previous fix, but less efficiently and without a regex group (link)