build: set default ts_devserver serving_path to /app_bundle.js to match g3 (#33996)

PR Close #33996

modules/playground/src/sourcemap/BUILD.bazel

@@ -1,5 +1,4 @@
-load("//tools:defaults.bzl", "ng_module")
-load("@npm_bazel_typescript//:index.bzl", "ts_devserver")
+load("//tools:defaults.bzl", "ng_module", "ts_devserver")
 
 package(default_visibility = ["//modules/playground:__subpackages__"])
 

modules/playground/src/sourcemap/index.html

@@ -11,7 +11,7 @@
   via source maps!
   </p>
 
-  <!--default load location for ts_devserver-->
-  <script src="/_/ts_scripts.js"></script>
+  <!--load location for ts_devserver-->
+  <script src="/app_bundle.js"></script>
 </body>
 </html>