feat: add test for missing @redocly/config type

[AlbinaBlazhko17]

What/Why/How?

We faced the issue when updating the version of openapi-core in other products. The problem was that we forgot to add new types in @redocly/config.

I created a unit test, which will fail if we forget to add types.

Reference

Discovered issue in PR #18391.

Testing

Manually.

Screenshots (optional)

Check yourself

• [ ] Code changed? - Tested with Redoc/Realm/Reunite (internal)
• [ ] All new/updated code is covered by tests
• [ ] New package installed? - Tested in different environments (browser/node)
• [x] Documentation update considered

Security

• [x] The security impact of the change has been considered
• [x] Code follows company security practices and guidelines

[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: 5a79614b83b600d59991731d63b1b1ccce1c448d

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[github-actions[bot]]

Command	Mean [s]	Min [s]	Max [s]	Relative
redocly lint packages/core/src/benchmark/benches/rebilly.yaml	1.408 ± 0.027	1.377	1.451	1.00
redocly-next lint packages/core/src/benchmark/benches/rebilly.yaml	1.410 ± 0.024	1.383	1.461	1.00 ± 0.03