Add Feast API scopes for "Saved from web" endpoints

[andresilva-guardian]

What are you changing?

• We added two new OAuth scopes to the scopes array in getIdentityAuth() in index.ts, guardian.feast-api.saved-from-web.update.self and guardian.feast-api.saved-from-web.read.self, each with an inline comment explaining what it grants
• We kept every existing scope in place, unchanged and in the same order
• We added a changeset, moody-seas-sing.md, marking this as a minor version bump for @guardian/identity-auth-frontend
• We ran the package's existing test suite to confirm nothing else broke

Why?

• Dotcom-rendering, and any other consumer of @guardian/identity-auth-frontend, needs to request access tokens that are valid for the new "Saved from web" endpoints on the Feast API, added in personalised-app-experience#256
• PUT /v2/saved-from-web/{recipeId} requires the guardian.feast-api.saved-from-web.update.self scope, and GET /v2/saved-from-web/{recipeId} requires the guardian.feast-api.saved-from-web.read.self scope
• These scopes have already been added to the "theguardian" Okta OAuth client in the identity-platform repo's Okta Terraform, so Okta will allow them to be requested, and consent is implicit, so we don't need any consent screen or UI changes
• We are keeping these scopes in the single global scopes array, consistent with how every other scope in this list is handled today, since this package doesn't support per-feature or per-call scoping

[changeset-bot]

🦋 Changeset detected

Latest commit: 840eda5

The changes in this PR will be included in the next version bump.

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[github-actions]

Tip

Once this PR is ready to go, add the run_chromatic label to run the Chromatic tests.

This saves us a lot of money by not running the tests before we need them.

[AshCorr]

We ran the package's existing test suite to confirm nothing else broke

Not entirely sure the packages test suite is broad enough to verify the interaction between DCR <-> @guardian/identity-auth <-> Gateway

Might be worth doing a pre-release by adding the "🐥 Canaries" label to this PR, so you can test this change in DCR CODE? I'm not entirely sure how @guardian/identity-auth behaves when a new scope is added, it shouldn't break, but I'm slightly worried about it signing users out who are missing the scope resulting in everyone getting signed out.