Use scudo_stack_depot_size from process_info

This is a no-op but will be used in upcoming scudo changes that allow to
change the depot size at process startup time, and as such we will no
longer be able to call __scudo_get_stack_depot_size in debuggerd.

We already did the equivalent change for the ring buffer size in
https://r.android.com/q/topic:%22scudo_ring_buffer_size%22

Bug: 309446692
Change-Id: I761a7602c54a1f8f2d0575c5e011820d8dbaab63