Adds privacy manifests to all iOS plugins.
While we only *need* to do the plugins listed [here](https://developer.apple.com/support/third-party-SDK-requirements/) for now, the wording of the page:
> The following are commonly used SDKs in apps on the App Store
suggests that the list of things for which this is required is just an arbitrary cutoff rather than a conceptual distinction, so it seems safest to just assume the list will grow over time and do all of them. To ensure that, this includes new repo tooling to check that a manifest is specified in the podspec.
The large caveat is that we do not currently know if this actually works. This is the method of inclusion that seems to be [the consensus among people using Cocoapods](https://github.com/CocoaPods/CocoaPods/issues/10325), as bundling it directly as a `resource` causes problems for clients who do not use `use_frameworks`. (In theory it seems like a manifest would not actually be *required* in that case since there is no framework, but it has the potential to actually stomp top-level resources.) Hopefully the automated analysis that Apple will eventually roll out will tolerate the file being bundled in a resource bundle in the framework rather than a top-level manifest file. If not, however, it's not clear how Cocoapods can be supported, so we can adopt this common approach for now under the assumption that eventually tooling will adapt to the reality of the ecosystem, and revisit the exact bundling later if necessary.
Only `shared_preferences` has a non-empty manifest, as it is our only plugin that uses a required reason API, and none of our plugins themselves collect private data. Ideally for that plugin we would instead use `C56D.1`, which is for wrappers, but as currently written we can't use it since it's exclusively a wrapper. If that changes in the future based on our pending request, we can revisit. For now, however, this reason should suffice since we don't currently allow reading from other app groups.
Fixes https://github.com/flutter/flutter/issues/131495
Fixes https://github.com/flutter/flutter/issues/139756
Fixes https://github.com/flutter/flutter/issues/139757
Fixes https://github.com/flutter/flutter/issues/139758
Fixes https://github.com/flutter/flutter/issues/139759
Fixes https://github.com/flutter/flutter/issues/139760
See also https://github.com/flutter/flutter/issues/139761
The Flutter build process creates podspecs that are just shims pointing to the local Flutter framework, and which don't pass the linter since they aren't intended for publishing. When finding podspecs to lint, skip those.
This avoids incorrect failures when running on a tree that isn't clean (in particular, where macOS and/or iOS builds have happened), which is very common locally.
Updates links and references to `flutter/plugins` to use `flutter/packages` instead, including making the `repository` pubspec.yaml check stricter in the repo tooling to ensure all packages are pointing to the right place.
Exceptions to the updates are:
- Changelog entries.
- Links to pull requests.
This will re-publish all the moved plugins, thus fixing the current redness of `release` (due to the current versions not being tagged in this repository).
