Resolves #8428

Changes:

• Fixes a regression where textToModel(' ') would throw instead of returning an empty geometry.
• Restores the behavior from earlier 2.x versions by returning an empty p5.Geometry when no contours are present.
• Prevents crashes in sketches that include space characters (e.g. Typography 2.0 tutorial).

PR Checklist

• npm run lint passes
• Inline reference is included / updated
• Unit tests are included / updated