Blender Git Loki

Fix T87080: Select shortest path fails in face mode

Regression in 80cbbd2843c2358879b1a710d81a3b41e1468327.

Unfortunately keeping selection picking behavior as well as
supporting finding the nearest face within a radius requires an
inconsistency between x-ray and back-buffer selection that
doesn't work well using the current arguments.

Resolve by adding an argument that causes the input distance
to be ignored for back-buffer selection.

This is used by selection picking but not the knife tool.

This changes behavior for path-selection in face mode,
which now uses a margin for back-buffer selection.

From my own testing this doesn't seem to be a problem like it could be
for regular selection picking.