Use runtime_libs for the dlopen dependency on libartpalette-system.

That will propagate it into requireNativeLibs in the ART APEX manifest.

Test: cat out/soong/.intermediates/art/build/apex/com.android.art/android_common_com.android.art_image/apex_manifest_full.json
  check that requireNativeLibs contains libartpalette-system.so
Bug: 130340935
Change-Id: I09c4030a9c585f10e730b192e7a03c8d87e2d8f3