Previously this option seemed to be the sole responsible for enabling
physics processing in Viewport, while several other features like
tooltips and debugging collision hints rely on it.
All this logic is moved to internal processing (it's incorrect to let
it be affected by users disabling physics/idle processing), and disabling
physics object picking no longer affects the internal physics processing.
Fixes#17001.
(cherry picked from commit ce7da2c7d6)