Deprecate amp-ad-custom completely (#40300)

Author: powerivq

build-system/compile/bundles.config.extensions.json

@@ -78,11 +78,6 @@
       "hasCss": true
     }
   },
-  {
-    "name": "amp-ad-custom",
-    "version": "0.1",
-    "latestVersion": "0.1"
-  },
   {
     "name": "amp-ad-exit",
     "version": "0.1",

build-system/compile/bundles.legacy-latest-versions.jsonc

@@ -14,7 +14,6 @@
   "amp-access": "0.1",
   "amp-accordion": "0.1",
   "amp-action-macro": "0.1",
-  "amp-ad-custom": "0.1",
   "amp-ad-exit": "0.1",
   "amp-ad-network-adsense-impl": "0.1",
   "amp-ad-network-adzerk-impl": "0.1",

build-system/test-configs/dep-check-config.js

@@ -157,11 +157,6 @@ exports.rules = [
       'extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js->extensions/amp-a4a/0.1/signature-verifier.js',
 
       // And a few more things depend on a4a.
-      'extensions/amp-ad-custom/0.1/amp-ad-custom.js->extensions/amp-a4a/0.1/amp-ad-network-base.js',
-      'extensions/amp-ad-custom/0.1/amp-ad-custom.js->extensions/amp-a4a/0.1/amp-ad-type-defs.js',
-      'extensions/amp-ad-custom/0.1/amp-ad-custom.js->extensions/amp-a4a/0.1/name-frame-renderer.js',
-      'extensions/amp-ad-custom/0.1/amp-ad-custom.js->extensions/amp-a4a/0.1/template-renderer.js',
-      'extensions/amp-ad-custom/0.1/amp-ad-custom.js->extensions/amp-a4a/0.1/template-validator.js',
       'extensions/amp-ad-network-adzerk-impl/0.1/amp-ad-network-adzerk-impl.js->extensions/amp-a4a/0.1/amp-ad-template-helper.js',
       'extensions/amp-ad-network-adzerk-impl/0.1/amp-ad-network-adzerk-impl.js->extensions/amp-a4a/0.1/amp-ad-type-defs.js',
       'extensions/amp-ad-network-adzerk-impl/0.1/amp-ad-network-adzerk-impl.js->extensions/amp-a4a/0.1/amp-ad-utils.js',
@@ -359,8 +354,6 @@ exports.rules = [
         'src/service/video-manager-impl.js',
       'extensions/amp-connatix-player/0.1/amp-connatix-player.js->' +
         'src/service/video-manager-impl.js',
-      'extensions/amp-a4a/0.1/friendly-frame-util.js->' +
-        'src/service/url-replacements-impl.js',
       'extensions/amp-nexxtv-player/0.1/amp-nexxtv-player.js->' +
         'src/service/video-manager-impl.js',
       'extensions/amp-3q-player/0.1/amp-3q-player.js->' +