Do not install prebuilt stubs from module_sdk

This is a rework of commit 5bdf2d58
which made implementation variant of prebuilts with stubs as not
installable except libclangrt. This change narrows the affected modules
to prebuilts/module_sdk because cc_prebuilt_library_shared with stub
implementation is a special case only used there. It's typical for
cc_prebuilt_library_shared to have implementation, not stub.

Bug: 220898484
Test: ART_MODULE_BUILD_FROM_SOURCE=false m nothing
Change-Id: I99e5213da8cc473901e23942b50f06c023d91f60