Make droid always depend on symbols zip

Currently the symbols.zip is only generated in dist builds, and are not
generated by default when running a default build (i.e. `m`). This
change enables the symbols.zip to be generated when running a default
build, and the symbols staging dir to be generated.

Test: m nothing && inspect ninja graph
Bug: 421023353
Change-Id: Ic24ea0da5c7f547372ab8353f170abd9ee266b3f