Drop iOS 14 Support: Increase deployment target to iOS 15

[kean]

Related Issue #20860

Bump the deployment target to iOS 15 and remove the now redundant #available checks and the associated code.

To test: make sure it still compiles and runs (run some basic smoke tests)

Regression Notes

1. Potential unintended areas of impact: n/a
2. What I did to test those areas of impact (or what existing automated tests I relied on): n/a
3. What automated tests I added (or what prevented me from doing so): n/a

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.

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	App Name	WordPress Alpha
	Configuration	Release-Alpha
	Build Number	pr20917-55b7b5c
	Version	22.6
	Bundle ID	org.wordpress.alpha
	Commit	55b7b5c
	App Center Build	WPiOS - One-Offs #6072

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[wpmobilebot]

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

	App Name	Jetpack Alpha
	Configuration	Release-Alpha
	Build Number	pr20917-55b7b5c
	Version	22.6
	Bundle ID	com.jetpack.alpha
	Commit	55b7b5c
	App Center Build	jetpack-installable-builds #5098

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[hassaanelgarem]

Thanks for wrangling this @kean!

[guarani]

I noticed the test plan only calls for the CI to be green. Do you think smoke testing of the build should be done? I'm not sure what testing has already been done.

With the next release being cut in on Monday (see PaaHJt-eZ-p2), I'm wondering if there's enough time this week for any issues related to the deployment target bump to be caught on the trunk branch.

[kean]

I noticed the test plan only calls for the CI to be green. Do you think smoke testing of the build should be done? I'm not sure what testing has already been done.

I've been testing previous PRs individually, and I've also did quick regression testing yesterday.

With this PR, it's hard to pinpoint what areas to test, but I at least tested the main areas of the app.

I'm wondering if there's enough time this week for any issues related to the deployment target bump to be caught on the trunk branch.

I think it should be OK, but we could wait until Tuesday to merge it. There is no rush. But most of the related changes were already merged.

[guarani]

I've been testing previous PRs individually, and I've also did quick regression testing yesterday.
With this PR, it's hard to pinpoint what areas to test, but I at least tested the main areas of the app.

Ok, I did a quick tap through the JP and WP app builds to try to catch regressions and had none.

I think it should be OK, but we could wait until Tuesday to merge it. There is no rush. But most of the related changes were already merged.

Ok, if we merge today there's only today and tomorrow to catch issues before the next beta (22.7). However, I don't see a big risk here as I've gone through the code changes and nothing looks out of place.

As for the actual deployment target change from 14 to 15, I can't think of any bugs that could come of that.

So, feel free to merge this week or next 👍

Thanks for your work, @kean!

[mokagio]

Ok, if we merge today there's only today and tomorrow to catch issues before the next beta (22.7). However, I don't see a big risk here as I've gone through the code changes and nothing looks out of place.

On top of that, I would argue that only major issues would be noticed because we don't distribute nightly builds from trunk and don't have a mechanism for a large enough pool of folks using the app not smoke testing it to get their hands on these changes.

[kean]

Hey, @guarani. The release branch was cut, so I'm planning to merge it today, and then I'll continue working on the remaining deprecations when I have time. I'm prioritizing the work on Blaze.