Geometry Nodes: Allow for one vertex in grid node

This commit allows setting the number of vertices in either direction
to 1, so that the primitive grid node will create a line instead of a
grid. To avoid confusion the soft limits of the input sockets are not
changed, so this is purely an increase in flexibility for when it is
helpful.

Differential Revision: https://developer.blender.org/D11772

Fix: Circle mesh primitive outer edges do not render

The outer edges created om the circle mesh primitive node
weren't marked with the flags that makes them show in wireframe
mode.

Differential Revision: https://developer.blender.org/D12152

Fix: Avoid floating point error in some mesh primitive nodes

Some mesh primitives created using geometry nodes use loops to create
vertices and accumulates positions/angles in FP variables. This allows
rounding errors to accumulate and can introduce significant errors.

To minimize changes from original implementation, variables allowing
errors to accumulate are replaced by: delta * index. Affected Mesh
Primitives nodes are Line, Grid, Cylinder, Circle, Cone, and UV-Sphere.

Differential Revision: https://developer.blender.org/D12136

Fix: Avoid floating point error in some mesh primitive nodes

Some mesh primitives created using geometry nodes use loops to create
vertices and accumulates positions/angles in FP variables. This allows
rounding errors to accumulate and can introduce significant errors.

To minimize changes from original implementation, variables allowing
errors to accumulate are replaced by: delta * index. Affected Mesh
Primitives nodes are Line, Grid, Cylinder, Circle, Cone, and UV-Sphere.

Differential Revision: https://developer.blender.org/D12136