dzn: Use narrow quadrilateral lines when supported

dzn: Use narrow quadrilateral lines when supported

This lets us follow the Vulkan spec requirements for MSAA line
rasterization, using a width of 1.0 instead of D3D's proscribed
width of 1.4. There's no reason to predicate this on MSAA being
enabled, since quadrilateral lines with a width of 1.0 are actually
the most desired type of line rasterization for Vulkan.

Follow-ups:
- We can probably turn on 'strict lines' when this is supported.
- We should enable the line rasterization mode extension.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22606>