Remove androidx prebuilts projects from dackka manifest

The prebuilts/dackka project now contains the prebuilts that dackka
needs.

Bug: 500091616
Test: ./gradlew
Change-Id: I376ab74a59b66698f82e5b1a244ce41683a345ce
1 file changed
tree: e96d4b944eda01b567eb54cd5bd1188d9962ff81
  1. default.xml