As of Xcode 15 on macOS Sonoma, the following message is (repeatedly)
output to stderr during builds (repros on non-Flutter apps). It is
supppressed in xcode itself, but not when run from the command-line.

```
2023-11-10 10:44:58.031 xcodebuild[61115:1017566] [MT] DVTAssertions: Warning in /System/Volumes/Data/SWE/Apps/DT/BuildRoots/BuildRoot11/ActiveBuildRoot/Library/Caches/com.apple.xbs/Sources/IDEFrameworks/IDEFrameworks-22267/IDEFoundation/Provisioning/Capabilities Infrastructure/IDECapabilityQuerySelection.swift:103
Details:  createItemModels creation requirements should not create capability item model for a capability item model that already exists.
Function: createItemModels(for:itemModelSource:)
Thread:   <_NSMainThread: 0x6000027c0280>{number = 1, name = main}
Please file a bug at https://feedbackassistant.apple.com with this warning message and any useful information you can provide.
```

This suppresses this message from stderr in our macOS build logs.

Issue: https://github.com/flutter/flutter/issues/135277

## Pre-launch Checklist

- [X] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [X] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [X] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [X] I signed the [CLA].
- [X] I listed at least one issue that this PR fixes in the description
above.
- [X] I updated/added relevant documentation (doc comments with `///`).
- [X] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [X] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#overview
[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
[test-exempt]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes
[Discord]: https://github.com/flutter/flutter/wiki/Chat