Remove iAd (Apple Search Ads) attribution

[jkmassel]

We're not purchasing ads for the app, and this code is deprecated. Let's remove it for now.

Includes some Xcode project cleanup noise

Regression Notes

1. Potential unintended areas of impact

2. What I did to test those areas of impact (or what existing automated tests I relied on)

3. What automated tests I added (or what prevented me from doing so)

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

Testing checklist:

• WordPress.com sites and self-hosted Jetpack sites.
• Portrait and landscape orientations.
• Light and dark modes.
• Fonts: Larger, smaller and bold text.
• High contrast.
• VoiceOver.
• Languages with large words or with letters/accents not frequently used in English.
• Right-to-left languages. (Even if translation isn’t complete, formatting should still respect the right-to-left layout)
• iPhone and iPad.
• Multi-tasking: Split view and Slide over. (iPad)

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📲 You can test the changes from this Pull Request in Jetpack Alpha by scanning the QR code below to install the corresponding build.

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[kean]

LGTM.

It seems that this API is not only deprecated but is also no longer working:

After February 7, 2023, all requests made to the Apple Search Ads iAd Attribution API will return with a value of "iad-attribution" = false, or errors. See ADClient/requestAttributionDetails(_:).

Source: https://developer.apple.com/documentation/iad/setting-up-apple-search-ads-attribution

There was a relatively recent search ad-campaign, but I'm not sure if it used the attribution info. It's reasonable to assume that if we run one again, we'll need to add a new attribution tracking code.