Prevent 'too small' starts from not rendering.

Not actually part of CURA-12188 but I was in the neighbourhood anyway.

plugins/SimulationView/layers3d.shader

@@ -360,8 +360,8 @@ geometry41core =
             ((v_prev_line_type[0] != 1) && (v_line_type[0] == 1)) ||
             ((v_prev_line_type[0] != 4) && (v_line_type[0] == 4))
             )) {
-            float w = size_x;
-            float h = size_y;
+            float w = max(0.05, size_x);
+            float h = max(0.05, size_y);
 
             myEmitVertex(v_vertex[0] + vec3( w,  h,  w), u_starts_color, normalize(vec3( 1.0,  1.0,  1.0)), viewProjectionMatrix * (gl_in[0].gl_Position + vec4( w,  h,  w, 0.0))); // Front-top-left
             myEmitVertex(v_vertex[0] + vec3(-w,  h,  w), u_starts_color, normalize(vec3(-1.0,  1.0,  1.0)), viewProjectionMatrix * (gl_in[0].gl_Position + vec4(-w,  h,  w, 0.0))); // Front-top-right