Do not replace the direct edge between rdeps and java_sdk_library

android/prebuilt.go#isSelected has a special-case inside it to ignore
apex_contributions contents for the top-level java_sdk_library hook.
This was necessary because even though we might want source stubs in
next builds, we still needed the top-level prebuilt hook to be active to
emit the dexpreopt rules to .mk.

This worked fine for rdeps that create a dependency edge on the child
stub modules of java_sdk_library. Notable examples include the full
android api stubs created by f/b/api.go. In postdeps mutator, these
expanded deps get rewritten to source/prebuilt if necesssry.

The exception to this are workflows which depend on the top-level hook
directly via `libs`. We resolve these rdeps to an appropriate provider
during GenerateAndroidBuildActions stage. This meant that rdeps were
getting prebuilt stubs of these even in next builds.

Bug: 323454855

Test: Added a unit test

Test: lunch cf_x86_64_only_phone-next-userdebug
Test: aninja -t query
out/soong/.intermediates/packages/modules/Permission/SafetyCenter/Config/safety-center-config/android_common/javac/safety-center-config.jar
| grep prebilts/module_sdk # empty now

Change-Id: Id91333d88055519f3c58ab40466f9628085f5180