feat(api): respond with 200/201 with empty json for successful PUT

[slonka]

Motivation

In our OpenAPI spec we say that we're returning application/json for put 200/201

kuma/tools/openapi/templates/endpoints.yaml

Line 63 in a00b2e0

application/json:

and we don't always do that. I can't find a way to describe this with OpenAPI schema (either you don't set content or you set it, there is no oneOf on that level). I tried this:

      responses:
        '200':
          description: Updated
          content:
            application/json:
              schema:
                oneOf:
                  - $ref: '#/components/schemas/MeshCreateOrUpdateSuccessResponse'
                  - type: 'null'

If we don't do this change terraform does not like the response not having content type:

╷
│ Error: failure to invoke API
│
│   with konnect_mesh.default,
│   on main.tf line 24, in resource "konnect_mesh" "default":
│   24: resource "konnect_mesh" "default" {
│
│ unknown content-type received: : Status 200
╵

Implementation information

Respond with 200/201 and empty {} when there are no errors.

Supporting documentation

xrel https://github.com/Kong/kong-mesh/issues/7201

[github-actions]

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[lahabana]

@slonka title of the PR needs updating