Bumps [jwks-rsa](https://github.com/auth0/node-jwks-rsa) from 4.0.1 to 4.1.0.
- [Release notes](https://github.com/auth0/node-jwks-rsa/releases)
- [Changelog](https://github.com/auth0/node-jwks-rsa/blob/master/CHANGELOG.md)
- [Commits](auth0/node-jwks-rsa@v4.0.1...v4.1.0)

---
updated-dependencies:
- dependency-name: jwks-rsa
  dependency-version: 4.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Bumps [google-auth-library](https://github.com/googleapis/google-cloud-node/tree/HEAD/core/packages/google-auth-library-nodejs) from 10.9.0 to 11.1.0.
- [Release notes](https://github.com/googleapis/google-cloud-node/releases)
- [Changelog](https://github.com/googleapis/google-cloud-node/blob/main/core/packages/google-auth-library-nodejs/CHANGELOG.md)
- [Commits](https://github.com/googleapis/google-cloud-node/commits/google-auth-library-v11.1.0/core/packages/google-auth-library-nodejs)

---
updated-dependencies:
- dependency-name: google-auth-library
  dependency-version: 11.0.2
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Bumps [sinon](https://github.com/sinonjs/sinon) and [@types/sinon](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/sinon). These dependencies needed to be updated together.

Updates `sinon` from 22.0.0 to 22.1.0
- [Release notes](https://github.com/sinonjs/sinon/releases)
- [Changelog](https://github.com/sinonjs/sinon/blob/main/CHANGES.md)
- [Commits](sinonjs/sinon@v22.0.0...v22.1.0)

Updates `@types/sinon` from 21.0.1 to 22.0.0
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/sinon)

---
updated-dependencies:
- dependency-name: "@types/sinon"
  dependency-version: 22.0.0
  dependency-type: direct:development
  update-type: version-update:semver-major
- dependency-name: sinon
  dependency-version: 22.1.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* feat(messaging): migrate topic subscriptions to FCM v1 API

Migrate `subscribeToTopic` and `unsubscribeFromTopic` methods in `admin.messaging.Messaging` from legacy Instance ID (IID) endpoints (`iid.googleapis.com/iid/v1`) to the modernized single-token Firebase Cloud Messaging (FCM) v1 Topics Subscription REST API (`fcm.googleapis.com/v1`).

- Update `subscribeToTopic` (`CreateTopicSubscription`) and `unsubscribeFromTopic` (`DeleteTopicSubscription`) to use HTTP/2 transport by default (or HTTP/1.1 via `enableLegacyHttpTransport()`).
- Implement client-side concurrency pooling (`runWithConcurrencyLimit`) bounded to 100 concurrent requests per batch to avoid HTTP/2 stream exhaustion.
- Preserve idempotency by treating `ALREADY_EXISTS` (HTTP 409) as success for subscription requests, and `NOT_FOUND` (HTTP 404) as `REGISTRATION_TOKEN_NOT_REGISTERED` for unsubscription requests.
- Add legacy backup/escape-hatch methods `subscribeToTopicLegacy` and `unsubscribeFromTopicLegacy` annotated with `@deprecated Use {@link Messaging.subscribeToTopic} instead.` and `@deprecated Use {@link Messaging.unsubscribeFromTopic} instead.`.

TAG=agy
CONV=a2576aae-730b-4fb1-a151-9e6913f97be4

* fix lint errors

* address PR feedback

* refactor duplicate code

* fix(messaging): capture HTTP/2 session errors in topic management requests

* fix(messaging): map UNREGISTERED error code to registration-token-not-registered in topic management

* refactor(messaging): address PR review feedback