fix open component modal jqlite compatibility

[navarroaxel]

fix issue #6186.
Works fine with legacy controller modals and component modals.

[navarroaxel]

in jQuery the the .html() method calls .empty().append() internally.
in jqlite the .html() set the HTMLElement into the innerHTML attribute of the parent element, so the .toString() method is called and displayed into the rendered HTML.

The solution for this was call the .append() method directly and the .empty() is not necessary because the parent is new and empty.

[wesleycho]

Good catch! Thanks for the PR!