chore(eventbroker): replace axios and related nock tests

[toufali]

Because

• axios is a recurring source of security advisories. This is the first step of removing it in favor of native fetch (FXA-13427), starting with the self-contained fxa-event-broker package.

This pull request

• Replaces axios with native fetch in ClientCapabilityService, PubsubProxyController, and the simulate-webhook-call script. Behavior is preserved (explicit !res.ok handling, JSON-with-text-fallback body parsing).
• Migrates the affected specs off nock to a stubbed global.fetch, and adds coverage for the non-ok HTTP path.
• Removes the now-unused axios and nock dependencies from the package.

Issue that this pull request solves

Closes: FXA-13427 (event-broker package)

Checklist

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• My commit is GPG signed.
• If applicable, I have modified or added tests which pass locally.
• I have added necessary documentation (if appropriate).
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[Copilot]

Pull request overview

This PR removes axios (and related nock-based tests) from the fxa-event-broker package, migrating the affected code paths to native fetch to reduce dependency/security advisory surface area.

Changes:

• Replaced axios usages with fetch in the pubsub proxy controller, client capability service, and the webhook simulation script.
• Migrated tests from nock to global.fetch stubs, including coverage for non-OK HTTP responses.
• Removed axios and nock from fxa-event-broker dependencies and simplified Jest config accordingly.

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
yarn.lock	Removes axios/nock from the fxa-event-broker workspace dependency set.
packages/fxa-event-broker/src/scripts/simulate-webhook-call.ts	Switches webhook call simulation from axios to fetch.
packages/fxa-event-broker/src/pubsub-proxy/pubsub-proxy.controller.ts	Replaces axios proxying with fetch, adds JSON-with-text-fallback response parsing helper.
packages/fxa-event-broker/src/pubsub-proxy/pubsub-proxy.controller.spec.ts	Replaces nock HTTP mocking with global.fetch stubs and adds a non-OK response test.
packages/fxa-event-broker/src/client-capability/client-capability.service.ts	Replaces axios client capability fetch with fetch and explicit non-OK handling.
packages/fxa-event-broker/src/client-capability/client-capability.service.spec.ts	Updates tests to stub global.fetch and adds coverage for reject + non-OK paths.
packages/fxa-event-broker/package.json	Removes axios and nock dependencies from the package.
packages/fxa-event-broker/jest.config.js	Removes the special-case transform for axios.

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