Refactor RenderAreaFuture to use RenderAreaBuilder

Cleans up renderArea logic and allows all the work that needs
to be done on the main thread in the same place. This will aid
in the effort to reduce the number of hops to the SF main
thread during screenshots.

Bug: b/294936197
Test: atest SurfaceFlinger_test
Test: presubmit
Change-Id: I4234b49638aaecceb8d1fcff7f5cd43698b6c47f