Today, we treat Xcode warnings as errors on all iOS and macOS plugins.
However, the google_sign_in_ios plugin has dependencies with warnings. We're unable to suppress these warnings when using Swift Package Manager. As a workaround, we'll need to disable Xcode warnings for the google_sign_in_ios plugin. This will be done in a subsequent pull request (see https://github.com/flutter/packages/pull/7356).
This change introduces `--xcode-warnings-exceptions` to the `native-test` command. When running Xcode test, `GCC_TREAT_WARNINGS_AS_ERRORS` will be provided only if the plugin isn't on the exception list.
Additionally, plugins that are the exception list are excluded from the `xcode-analyze` command.
Part of https://github.com/flutter/flutter/issues/146904
