[dart_flutter_team_lints] add strict_top_level_inference (#328)

- add the new `strict_top_level_inference` lint
- update the sdk dependency
- rev for publishing

Note that this won't build cleanly until a dev sdk is released that
contains `strict_top_level_inference`; I'll hold off on landing /
publishing this until then.

w/ the pubspec constraints here:
- most packages using this (^3.0.0) will solve for this new version of
the package
- they'll only get this version if they happen to be running `pub get`
on a 3.7 dev version of the sdk
- many repos in dart-lang will pick up this version, but only from the
build jobs running on a dev sdk

I think we can publish this and fix up the failing jobs reactively.

---

- [x] I’ve reviewed the contributor guide and applied the relevant
portions to this PR.

<details>
  <summary>Contribution guidelines:</summary><br>

- See our [contributor
guide](https://github.com/dart-lang/.github/blob/main/CONTRIBUTING.md)
for general expectations for PRs.
- Larger or significant changes should be discussed in an issue before
creating a PR.
- Contributions to our repos should follow the [Dart style
guide](https://dart.dev/guides/language/effective-dart) and use `dart
format`.
- Most changes should add an entry to the changelog and may need to [rev
the pubspec package
version](https://github.com/dart-lang/sdk/blob/main/docs/External-Package-Maintenance.md#making-a-change).
- Changes to packages require [corresponding
tests](https://github.com/dart-lang/.github/blob/main/CONTRIBUTING.md#Testing).

Note that many Dart repos have a weekly cadence for reviewing PRs -
please allow for some latency before initial review feedback.
</details>