## Context
This PR fixes a REST API metadata schema mismatch that occurred after
the webhook and apiKey migration from workspace entities to metadata
level.
## The Issue
After PR #13576 deleted the webhook and apiKey workspace entities, the
metadata OpenAPI specification ended up in a broken state:
- The `/metadata` endpoints still had paths for `/webhooks` and
`/apiKeys`
- But the schema definitions were missing (they were previously pulled
from workspace entities)
- This created dangling references in the OpenAPI document
## The Fix
Added proper schema definitions for webhook and apiKey directly in
`computeMetadataSchemaComponents`:
- `Webhook`, `WebhookForUpdate`, `WebhookForResponse`
- `ApiKey`, `ApiKeyForUpdate`, `ApiKeyForResponse`
## Why the CI is Failing
The CI breaking changes detection is comparing:
- **Main branch**: Has a broken OpenAPI document with endpoints that
reference non-existent schemas
- **This branch**: Has the fixed OpenAPI document with proper schemas
The OpenAPI diff tool can't even parse the main branch's document due to
the missing schema references, hence the error -- tested locally
It used to post a comment if the API schema changed, even if there's no
breaking change. I thought this could be OK as an FYI. But it is not
since now we generate the examples dynamically with Faker the OpenAPI
schema is always different
