refactor(@schematics/angular): remove version 16 migrations

This migrations are no longer needed

Author: alan-agius4

packages/schematics/angular/migrations/migration-collection.json

@@ -1,19 +1,3 @@
 {
-  "schematics": {
-    "remove-default-project-option": {
-      "version": "16.0.0",
-      "factory": "./update-16/remove-default-project-option",
-      "description": "Remove 'defaultProject' option from workspace configuration. The project to use will be determined from the current working directory."
-    },
-    "replace-default-collection-option": {
-      "version": "16.0.0",
-      "factory": "./update-16/replace-default-collection-option",
-      "description": "Replace removed 'defaultCollection' option in workspace configuration with 'schematicCollections'."
-    },
-    "update-server-builder-config": {
-      "version": "16.0.0",
-      "factory": "./update-16/update-server-builder-config",
-      "description": "Update the '@angular-devkit/build-angular:server' builder configuration to disable 'buildOptimizer' for non optimized builds."
-    }
-  }
+  "schematics": {}
 }