fix(testing): Use `@clerk/backend` package to fetch tokens

[anagstef]

Description

Drops the custom fetch to BAPI, and replaces it with using the @clerk/backend package.

Checklist

• [x] npm test runs as expected.
• [x] npm run build runs as expected.
• [ ] (If applicable) JSDoc comments have been added or updated for any package exports
• [ ] (If applicable) Documentation has been updated

Type of change

• [ ] 🐛 Bug fix
• [ ] 🌟 New feature
• [ ] 🔨 Breaking change
• [x] 📖 Refactoring / dependency upgrade / documentation
• [ ] other:

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 69e068495969c82524e7fa2dbcda511694413a7b

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

This PR includes changesets to release 1 package

| Name | Type | | -------------- | ----- | | @clerk/testing | Patch |

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[anagstef]

!snapshot

[clerk-cookie]

Hey @anagstef - the snapshot version command generated the following package versions:	Package	Version
gatsby-plugin-clerk	5.0.0-beta.45
@clerk/testing	1.1.10-snapshot.ve48d86f

Tip: Use the snippet copy button below to quickly install the required packages. gatsby-plugin-clerk

npm i gatsby-plugin-clerk@5.0.0-beta.45 --save-exact

@clerk/testing

npm i @clerk/testing@1.1.10-snapshot.ve48d86f --save-exact

[anagstef]

!snapshot

[clerk-cookie]

Hey @anagstef - the snapshot version command generated the following package versions:	Package	Version
gatsby-plugin-clerk	5.0.0-beta.45
@clerk/testing	1.1.10-snapshot.v69e0684

Tip: Use the snippet copy button below to quickly install the required packages. gatsby-plugin-clerk

npm i gatsby-plugin-clerk@5.0.0-beta.45 --save-exact

@clerk/testing

npm i @clerk/testing@1.1.10-snapshot.v69e0684 --save-exact

[dimkl]

@anagstef What was the reason behind this change?

[anagstef]

@dimkl Using our backend package is cleaner, instead of hitting our BAPI directly with a fetch