test: migrate remaining public-api tests to Bazel (#22639)

We now create npm packages to cover all the public api assertions in tools/public_api_guard.
We no longer depend on ts-api-guardian from npm - it is now stale since the repository was archived.
There is no longer a gulp task to enforce or accept the public API, this is in CircleCI as part of running all bazel test targets.

PR Close #22639

packages/platform-webworker/BUILD.bazel

@@ -1,6 +1,6 @@
 package(default_visibility = ["//visibility:public"])
 
-load("//tools:defaults.bzl", "ng_module")
+load("//tools:defaults.bzl", "ng_module", "ng_package")
 
 ng_module(
     name = "platform-webworker",
@@ -19,3 +19,12 @@ ng_module(
         "//packages/platform-browser",
     ],
 )
+
+ng_package(
+    name = "npm_package",
+    srcs = ["package.json"],
+    entry_point = "packages/platform-webworker/index.js",
+    deps = [
+        ":platform-webworker",
+    ],
+)