iOS 18 Support

[jkmassel]

Adds iOS 18 support – we're not building against that SDK yet, but right now this PR:

1. Adds iOS 18 tint-able icons
2. Builds the app with Xcode 16

To test: Ensure CI passes

[dangermattic]

	3 Warnings
:warning:	View files have been modified, but no screenshot or video is included in the pull request. Consider adding some for clarity.
:warning:	This PR is larger than 500 lines of changes. Please consider splitting it into smaller PRs for easier and faster reviews.
:warning:	This PR is assigned to the milestone 25.4. The due date for this milestone has already passed. Please assign it to a milestone with a later deadline or check whether the release for this milestone has already been finished.

Generated by :no_entry_sign: Danger

[wpmobilebot]

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

	App Name	WordPress Alpha
	Configuration	Release-Alpha
	Build Number	pr23527-d2410ee
	Version	25.3
	Bundle ID	org.wordpress.alpha
	Commit	d2410eebfb5d2825611e6c10f439f1ca8f940bd0
	App Center Build	WPiOS - One-Offs #10727

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.

[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	pr23527-d2410ee
	Version	25.3
	Bundle ID	com.jetpack.alpha
	Commit	d2410eebfb5d2825611e6c10f439f1ca8f940bd0
	App Center Build	jetpack-installable-builds #9771

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.