Allow tweaking minimum block size and max block ratio

The original settings of 48 and 0.05 resulted in very small results in
real-world use. The min edge length of 48 does not account for possible
padding and is unnecessarily small. The block ratio of 0.05 is probably
OK to exceed, and is unnecessarily limiting. It is worth noting that the
previous defaults usually caused a conflict between the min length and
max ratio.

Keep the parameters in case we change our mind later.

Test: TopologyScaleTest
Flag: com.android.settings.flags.display_topology_pane_in_display_list
Bug: b/352648432
Change-Id: If8f72dd2e0652ffb33f3d61b137ac7d64a4477f5