admin-ui-bundle 2.9.22: no second jQuery and YUI copies on legacy admin pages

Updated:

• The admin page head loads its own jQuery 2.1.4 and the YUI 3 seed only when the legacy page has not already loaded them. Two copies replaced the first one's plugins ($(...).EzTags is not a function, Y.one is not a function) on CJW Exponential Platform Nexus installs.

For the 2.x line (Platform 2.5 / Symfony 3.4).