Restore arc_tolerance value when using Clipper2's InflatePaths

[rburing]

This was missed when upgrading from Clipper to Clipper2.

The value used to be passed as the second argument to the ClipperOffset constructor here (with an inaccurate/outdated comment, as the default is 0.25 unscaled):

godot/core/math/geometry_2d.cpp

Line 293 in a8bc9f3

ClipperOffset co(2.0, 0.25f * (real_t)SCALE_FACTOR); // Defaults from ClipperOffset.

Now we set the same parameter in Clipper2 by passing it to InflatePaths.

• Fixes The efficiency of Geometry2D polygon offset with JOIN_ROUND operation has slowed down significantly in 4.3 #97964

The MRP now yields results and timings of the same order of magnitude as with Clipper in 4.2.2:

4.2.2 offset join round:
execution time: 46034
result size: 23 

4.2.2 offset join miter:
execution time: 24829
result size: 7 

4.4 offset join round:
execution time: 51572
result size: 25

4.4 offset join miter:
execution time: 25920
result size: 7 

[clayjohn]

Thank you!