Remove `read_connector_secrets` cluster privilege

[n1v0lg]

ES PR https://github.com/elastic/elasticsearch/pull/110414 removes read_connector_secrets -- this cluster privilege was introduced for an undocumented beta API. It was never meant to be user-facing, and instead meant to be used by an internal service account. Since there is no need for this privilege for end-users, and it grants access to an internal API only, we have decided to remove it altogether and rely on raw action names for the internal service account's role instead.

This PR removes the privilege from the spec.

[l-trotta]

LGTM, just waiting for the validation to be available again

[github-actions[bot]]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
security.activate_user_profile	:green_circle:	9/9	9/9
security.authenticate	:green_circle:	30/30	30/30
security.bulk_delete_role	:orange_circle:	Missing type	Missing type
security.bulk_put_role	:orange_circle:	Missing type	Missing type
security.bulk_update_api_keys	:orange_circle:	Missing type	Missing type
security.change_password	:green_circle:	9/9	9/9
security.clear_api_key_cache	:green_circle:	13/13	13/13
security.clear_cached_privileges	:green_circle:	3/3	3/3
security.clear_cached_realms	:green_circle:	1/1	1/1
security.clear_cached_roles	:green_circle:	2/2	2/2
security.clear_cached_service_tokens	:green_circle:	4/4	4/4
security.create_api_key	:red_circle:	67/69	60/60
security.create_cross_cluster_api_key	:orange_circle:	Missing type	Missing type
security.create_service_token	:green_circle:	3/3	3/3
security.delete_privileges	:green_circle:	6/6	6/6
security.delete_role_mapping	:green_circle:	9/9	9/9
security.delete_role	:green_circle:	8/8	8/8
security.delete_service_token	:white_circle:	Missing test	Missing test
security.delete_user	:green_circle:	9/9	9/9
security.disable_user_profile	:green_circle:	1/1	1/1
security.disable_user	:green_circle:	3/3	3/3
security.enable_user_profile	:green_circle:	1/1	1/1
security.enable_user	:green_circle:	4/4	4/4
security.enroll_kibana	:white_circle:	Missing test	Missing test
security.enroll_node	:white_circle:	Missing test	Missing test
security.get_api_key	:red_circle:	38/38	15/38
security.get_builtin_privileges	:red_circle:	2/2	1/2
security.get_privileges	:green_circle:	12/12	12/12
security.get_role_mapping	:red_circle:	18/18	10/18
security.get_role	:red_circle:	24/24	21/24
security.get_service_accounts	:white_circle:	Missing test	Missing test
security.get_service_credentials	:green_circle:	1/1	1/1
security.get_settings	:orange_circle:	Missing type	Missing type
security.get_token	:green_circle:	25/25	24/24
security.get_user_privileges	:red_circle:	8/8	7/8
security.get_user_profile	:green_circle:	8/8	8/8
security.get_user	:green_circle:	25/25	25/25
security.grant_api_key	:green_circle:	7/7	7/7
security.has_privileges_user_profile	:green_circle:	3/3	3/3
security.has_privileges	:green_circle:	24/24	24/24
security.invalidate_api_key	:green_circle:	12/12	12/12
security.invalidate_token	:green_circle:	11/11	11/11
security.oidc_authenticate	:orange_circle:	Missing type	Missing type
security.oidc_logout	:orange_circle:	Missing type	Missing type
security.oidc_prepare_authentication	:orange_circle:	Missing type	Missing type
security.put_privileges	:green_circle:	10/10	10/10
security.put_role_mapping	:red_circle:	2/11	11/11
security.put_role	:red_circle:	38/40	39/39
security.put_user	:green_circle:	49/49	48/48
security.query_api_keys	:red_circle:	14/14	1/14
security.query_role	:orange_circle:	Missing type	Missing type
security.query_user	:orange_circle:	Missing type	Missing type
security.saml_authenticate	:white_circle:	Missing test	Missing test
security.saml_complete_logout	:white_circle:	Missing test	Missing test
security.saml_invalidate	:white_circle:	Missing test	Missing test
security.saml_logout	:white_circle:	Missing test	Missing test
security.saml_prepare_authentication	:white_circle:	Missing test	Missing test
security.saml_service_provider_metadata	:white_circle:	Missing test	Missing test
security.suggest_user_profiles	:green_circle:	1/1	1/1
security.update_api_key	:green_circle:	5/5	5/5
security.update_cross_cluster_api_key	:orange_circle:	Missing type	Missing type
security.update_settings	:orange_circle:	Missing type	Missing type
security.update_user_profile_data	:green_circle:	1/1	1/1

You can validate these APIs yourself by using the make validate target.