scope: Don't stroke the scope's path

Stroking limits the usefulness of this function, as applications
may want to do something else than stroking the scope's path.

components/st3m/st3m_scope.c

@@ -110,6 +110,4 @@ void st3m_scope_draw(Ctx *ctx) {
         int y = scope.read_buffer[i] >> shift;
         ctx_line_to(ctx, x, y);
     }
-
-    ctx_stroke(ctx);
 }