fix(lines): add a check to prevent a crash

Signed-off-by: Schmarni <marnistromer@gmail.com>

src/nodes/drawable/lines.rs

@@ -194,6 +194,7 @@ fn build_line_mesh(
 				}
 				indices_set += 1;
 			}
+			if indices_set > 0 {
 				// Handle the connection between start and end points:
 				// - For cyclic lines: connect last segment back to first
 				// - For non-cyclic lines: add caps at both ends
@@ -204,6 +205,7 @@ fn build_line_mesh(
 					vertex_indices.extend(cap_indices(indices_set - 1, true));
 				}
 			}
+		}
 		let mut mesh = Mesh::new(
 			PrimitiveTopology::TriangleList,
 			RenderAssetUsages::RENDER_WORLD,