[Fleet] remove old bundled.yaml from oas, fixed tags

[juliaElastic]

Summary

Closes #184685

Release notes: These schema changes shouldn't be breaking, but there were some incorrect/missing response schemas in the old openapi spec.

For example the API POST /api/fleet/agents/{agentId}/actions response was incorrectly documented: https://petstore.swagger.io/?url=https://raw.githubusercontent.com/elastic/kibana/main/x-pack/plugins/fleet/common/openapi/bundled.json#/Elastic%20Agent%20actions/new-agent-action

{
  "body": [
    0
  ],
  "statusCode": 0,
  "headers": "string"
}

Fixed here: https://petstore.swagger.io/?url=https://raw.githubusercontent.com/elastic/kibana/31f8cfd6efc5e79255fec0dfbc1f735592736dad/oas_docs/bundle.json#/Elastic%20Agent%20actions/%252Fapi%252Ffleet%252Fagents%252F%257BagentId%257D%252Factions%230

{
  "item": {
    "ack_data": "string",
    "agents": [
      "string"
    ],
    "created_at": "string",
    "data": "string",
    "expiration": "string",
    "id": "string",
    "minimum_execution_duration": 0,
    "namespaces": [
      "string"
    ],
    "rollout_duration_seconds": 0,
    "sent_at": "string",
    "source_uri": "string",
    "start_time": "string",
    "total": 0,
    "type": "string"
  }
}

Note: Since the schema changes are only included in main branch (9.x) currently, changing to the openapi spec have to be manually done in the old files in the 8.x branch for backports.

The new spec should match the implementation accurately, and responses are being verified when returned. Tests were added to make sure the response schemas are correct.
If there are any bugs in the current schema, it will result in a HTTP 500 error with an error message on where the schema validation failed.
Example of an error where a field is missing:

{
    "statusCode": 500,
    "error": "Internal Server Error",
    "message": "Failed output validation: [request body.items.0.name]: definition for this key is missing"
}

Example of an error where a field is mandatory in the schema, but not provided in the response (missing schema.maybe)

{
    "statusCode": 500,
    "error": "Internal Server Error",
    "message": "Failed output validation: [request body.items.0.internal]: expected value of type [boolean] but got [undefined]"
}

There are a few places where the validation allows unknown fields. Used it where some fields were not included in TS types or fields are more dynamic, e.g. fields coming from packages or elasticsearch settings.
https://github.com/search?q=repo%3Aelastic%2Fkibana+extendsDeep+path%3A%2F%5Ex-pack%5C%2Fplugins%5C%2Ffleet%5C%2Fserver%5C%2Ftypes%5C%2F%2F&type=code

.extendsDeep({
  unknowns: 'allow',
 })

Changes in this pr:
Remove using old bundled.yaml to generate oas, fixed tags.
Removed old openapi files, updated readme.

Here is the new bundle in Swagger UI:
stateful
serverless

Updated serverless scripts too.

Updated Fleet readme: https://github.com/elastic/kibana/blob/da72ee0093c5a1e164b4a24c5f94333c2376e7cc/x-pack/plugins/fleet/common/openapi/README.md

Generated the new bundle by running this script locally:

node scripts/capture_oas_snapshot --include-path /api/fleet --update

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[criamico]

Thanks for adding the deprecations and for taking care of this migration!

Could you add a quick explanation on the readme on how to use this new system for the openapi, the commands etc? It's fine on another PR as well.

Also, is already possible to delete the old openapi specs after this PR is merged?

[criamico]

LGTM 🚀

[criamico]

Thanks for the updated readme!

[jbudz]

.buildkite/scripts/steps/capture_oas_snapshot.sh

[lcawl]

There are linting messages about missing descriptions for responses, for example, but IMO those can be added over time. LGTM

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 86ecafc

Metrics [docs]

✅ unchanged

History

• 💛 Build #239183 was flaky e51222f

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @juliaElastic