update TxnSendMailTo input js trigger for new version of jquery(1.9.1)

old version results in js syntax error :/

changes are:

* special chars in jquery selector shall be escaped now.
  see also http://api.jquery.com/category/selectors/

  so we switched to .filter instead to get around this(chmrr++), which is more
  elegant than escaping chars.

* .attr => .prop
  please check http://api.jquery.com/prop/ for the differences between them

see also #28127
Merge branch '4.2/txn-send-mail-to-input-js-trigger-for-jquery-1.9' into 4.2-trunk