[Podcast Feed Reload] Add tooltip

[danielebogo]

📘 Part of: #2703

This PR adds the tooltip to advise the user of the feed reload functionality.

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To test

• Make sure you have the podcastFeedUpdate FF enabled
• Make sure to enable the tracks logger
  • You can find both under Profile -> Cog icon at top right -> Beta Features
• Navigate to a podcast detail
• When the view appears confirm you see the tooltip (like the one in the screenshot above)
• Confirm you see 🔵 Tracked: podcast_refresh_episode_tooltip_shown
• Tap the view to dismiss it
• Confirm you see 🔵 Tracked: podcast_refresh_episode_tooltip_dismissed
• Navigate back
• Open a podcast again (same as before or a new one)
• Confirm the tooltip is not showed again

Checklist

• I have considered if this change warrants user-facing release notes and have added them to CHANGELOG.md if necessary.
• I have considered adding unit tests for my changes.
• I have updated (or requested that someone edit) the spreadsheet to reflect any new or changed analytics.

[danielebogo]

@SergioEstevao I extracted the body to a new View as I had many problems with the size returned by the geometry proxy. Using a static view and setting this sizingOptions = [.preferredContentSize] seems to work properly each time.