Allow bazel-bin to be accessed within bazel build sandbox

tools/build_rules/ui_bundle/esbuild.config.mjs

@@ -0,0 +1,8 @@
+export default {
+  alias: {
+    // We're adding the bazel-bin alias, so we can use generated files with
+    // that prefix to make Node tooling happy for IDEs/linters/etc. but
+    // also making it "just work" for Bazel.
+    'bazel-bin': '.',
+  }
+}