When navigating the samples were always reset. This was introduced
by 7ec59b05ff where samples needed
to be reset when painting.
This PR solves it by separating the navigation and the painting more
clearly in the API. Also cleans up some calls that are also encapsulated
via the EEVEE Instance class.
Validated that painting and navigating still worked with these changes
applied.
Pull Request: https://projects.blender.org/blender/blender/pulls/123064