CursorInputMapper: Use flat velocity params when acceleration is disabled

We still use velocity control params when the
enable_new_mouse_pointer_ballistics flag is disabled. For the old
pipeline, ensure we use flat velocity control params whenever
pointer acceleration is disabled for the associated display.

Bug: 323409820
Test: atest VirtualMouseTest#sendRelativeEvent --rerun-until-failure 100
Change-Id: Id411ee61809cb0a46413d109c03358be5457a8a6