Bug 36528: Correct JS assets included in self checkout slip template

Bug 36528: Correct JS assets included in self checkout slip template

The self checkout's slip print template includes some assets which it
doesn't need (enquire.js) and lacks other that it does (i18n-related
files). This patch correct the problem.

The patch also wraps some code in global.js with a check that the
relevant library has been loaded so that we don't get errors when the
asset isn't included.

To test, apply the patch and clear your browser cache.

- With WebBasedSelfCheck enabled, log in to the self checkout module and
  check some items out.
- Click "Finish" and then "Print receipt..."
- Check the browser console on the receipt page. There should be no
  errors.
- Log in to the OPAC and click the "Messaging" tab on the patron summary
  page.
- Test that the "Digests only" table heading icon shows a tooltip.
- Test that enquire.js is still loading correctly by performing a
  catalog search and narrowing your browser. When the window is narrow
  enough, the facets sidebar should collapse into a "Refine your search"
  button.

Note that the "js_in_body" qa warning is a false positive.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>