[DOCS] Fix OpenAPI error in OpenAI connector secrets (#244679)

(cherry picked from commit ea64620)

Author: lcawl

oas_docs/output/kibana.serverless.yaml

@@ -72774,7 +72774,6 @@ components:
           description: |
             Base64-encoded PEM CA certificate content for PKI authentication (Other provider only). Optional.
           minLength: 1
-      required: []
     opsgenie_secrets:
       title: Connector secrets properties for an Opsgenie connector
       required:

oas_docs/output/kibana.yaml

@@ -57442,7 +57442,6 @@ components:
           description: |
             Base64-encoded PEM CA certificate content for PKI authentication (Other provider only). Optional.
           minLength: 1
-      required: []
     opsgenie_secrets:
       title: Connector secrets properties for an Opsgenie connector
       required:

x-pack/platform/plugins/shared/actions/docs/openapi/components/schemas/genai_secrets.yaml

@@ -23,4 +23,3 @@ properties:
     description: |
       Base64-encoded PEM CA certificate content for PKI authentication (Other provider only). Optional.
     minLength: 1
-required: []