build(bazel): replace yarn_install(name = "npm") with @npm local_reporsitory() to speed up build (#27469)

PR Close #27469

tools/npm/package.json

@@ -1,14 +0,0 @@
-{
-  "description": "minimal @npm repo required to build @rxjs from source and so that @npm//@angular/bazel is a valid target",
-  "dependencies": {
-    "@angular/bazel": "6.1.9",
-    "@angular/compiler": "6.1.9",
-    "@angular/compiler-cli": "6.1.9",
-    "@bazel/karma": "0.21.0",
-    "@bazel/typescript": "0.21.0",
-    "typescript": "~3.1.1"
-  },
-  "scripts": {
-    "//": "TODO(gregmagolan): figure out how to keep @bazel/karma & @bazel/typescript dependencies here up to date with the root package.json; NOTE: versions of @angular/x don't matter here as they are only require to create the @npm//@angular/bazel target name"
-  }
-}