Reverts "[SwiftPM] Turn on by default (#161275)" (#161339)
<!-- start_original_pr_link -->
Reverts: flutter/flutter#161275
<!-- end_original_pr_link -->
<!-- start_initiating_author -->
Initiated by: loic-sharma
<!-- end_initiating_author -->
<!-- start_revert_reason -->
Reason for reverting: failing post submit check
`[build_ios_framework_module_test](https://ci.chromium.org/ui/p/flutter/builders/prod/Mac_arm64%20build_ios_framework_module_test)
```
[2025-01-08 14:19:48.853336] [STDOUT] stdout: ** BUILD SUCCEEDED **
[2025-01-08 14:19:50.360684] [STDOUT] stdout: [+1522 ms] ├─Building plugins... (completed in 4.8s)
[2025-01-08 14:19:50.360824] [STDOUT] stdout: [
<!-- end_revert_reason -->
<!-- start_original_pr_author -->
Original PR Author: loic-sharma
<!-- end_original_pr_author -->
<!-- start_reviewers -->
Reviewed By: {cbracken, vashworth, jmagman}
<!-- end_reviewers -->
<!-- start_revert_body -->
This change reverts the following previous change:
This turns on Swift Package Manager by default:
1. New apps will have Swift Package Manager integration
2. New plugins will support Swift Package Manager
3. Existing apps will continue to use CocoaPods. They can migrate to SwiftPM using `flutter config --enable-swift-package-manager-migration`.
See this mini design doc: https://github.com/flutter/flutter/issues/151567#issuecomment-2455941279
Here's the PR that updates the SwiftPM docs: https://github.com/flutter/website/pull/11495
Part of https://github.com/flutter/flutter/issues/151567
## 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] I followed the [breaking change policy] and added [Data Driven Fixes] where supported.
- [ ] 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/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]: https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]: https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#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/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]: https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]: https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md
<!-- end_revert_body -->
Co-authored-by: auto-submit[bot] <flutter-engprod-team@google.com>
05899f84c6