build: fix size-tracking tests not running (#31779)

Currently when someone wants to explicitly run the
size-tracking tool tests, the size-tracking tool never
runs because of recent changes for the rules_nodejs
update broke the `entry_point` attribute.

PR Close #31779

tools/size-tracking/index.bzl

@@ -25,7 +25,7 @@ def js_size_tracking_test(
         "@npm//source-map",
         "@npm//chalk",
     ]
-    entry_point = ":index.ts"
+    entry_point = "//tools/size-tracking:index.ts"
 
     nodejs_test(
         name = name,