Revert "Add bac to backend service (GoogleCloudPlatform#13213)"

This reverts commit 44c0fbb.

Author: porky256

mmv1/products/compute/BackendService.yaml

@@ -127,12 +127,6 @@ examples:
       default_neg_name: 'network-endpoint'
       health_check_name: 'health-check'
       network_name: 'network'
-  - name: 'backend_service_tls_settings'
-    primary_resource_id: 'default'
-    vars:
-      backend_service_name: 'backend-service'
-      health_check_name: 'health-check'
-      authentication_name: 'authentication'
 parameters:
 properties:
   - name: 'affinityCookieTtlSec'
@@ -1472,44 +1466,3 @@ properties:
     description: |
       URL to networkservices.ServiceLbPolicy resource.
       Can only be set if load balancing scheme is EXTERNAL, EXTERNAL_MANAGED, INTERNAL_MANAGED or INTERNAL_SELF_MANAGED and the scope is global.
-  - name: 'tlsSettings'
-    type: NestedObject
-    description: |
-      Configuration for Backend Authenticated TLS and mTLS. May only be specified when the backend protocol is SSL, HTTPS or HTTP2.
-    properties:
-      - name: 'sni'
-        type: String
-        description: |
-          Server Name Indication - see RFC3546 section 3.1. If set, the load balancer sends this string as the SNI hostname in the
-          TLS connection to the backend, and requires that this string match a Subject Alternative Name (SAN) in the backend's
-          server certificate. With a Regional Internet NEG backend, if the SNI is specified here, the load balancer uses it
-          regardless of whether the Regional Internet NEG is specified with FQDN or IP address and port.
-      - name: 'subjectAltNames'
-        type: Array
-        description: |
-          A list of Subject Alternative Names (SANs) that the Load Balancer verifies during a TLS handshake with the backend.
-          When the server presents its X.509 certificate to the Load Balancer, the Load Balancer inspects the certificate's SAN field,
-          and requires that at least one SAN match one of the subjectAltNames in the list. This field is limited to 5 entries.
-          When both sni and subjectAltNames are specified, the load balancer matches the backend certificate's SAN only to
-          subjectAltNames.
-        item_type:
-          type: NestedObject
-          properties:
-            - name: 'dnsName'
-              type: String
-              description: The SAN specified as a DNS Name.
-              exactly_one_of:
-                - tlsSettings.0.uniform_resource_identifier
-                - tlsSettings.0.dns_name
-            - name: 'uniformResourceIdentifier'
-              type: String
-              description: The SAN specified as a URI.
-              exactly_one_of:
-                - tlsSettings.0.uniform_resource_identifier
-                - tlsSettings.0.dns_name
-      - name: 'authenticationConfig'
-        type: String
-        description: |
-          Reference to the BackendAuthenticationConfig resource from the networksecurity.googleapis.com namespace.
-          Can be used in authenticating TLS connections to the backend, as specified by the authenticationMode field.
-          Can only be specified if authenticationMode is not NONE.