Use 'line-z-offset', lines cannot be vertical

Nobody has claimed this yet.

### mapbox-gl-js version

v3.17.0

### Browser and version

143.0.7499.170

### Expected behavior

I hope the lines can be vertical and look the same width in any direction
I think it's a bug that disappears vertically, and the issue of line width may be part of your design, but I also want to know if there's a way to set it up

### Actual behavior

In fact, when the line is completely vertical, it disappears, and the width of the line varies from different angles

### Link to the demonstration

_No response_

### Steps to trigger the unexpected behavior

The lines in the following code are vertical, but they are not displayed
Modifying latitude or longitude lines may result in varying widths when viewed from different angles
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### Relevant log output

```shell

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Start by tracing the rendering path for the line-z-offset and line-elevation-reference layout properties, then reproduce the vertical and changing-width cases described in the issue. Compare the behavior with nonvertical lines and determine whether the fix belongs in line rendering or property handling; add regression coverage for the confirmed behavior.

Written by the indexing model from the issue text.