MdeModulePkg:Add ESC key support in setup browser pop-up message box

MdeModulePkg:Add ESC key support in setup browser pop-up message box

When load default value or save changes will pop up message box to let user
confirm,Y means confirm and N means ignore,now add Esc key with the
same function of N key.And change the content of pop up message in .uni file,
now will display "Press 'Y' to confirm, 'N'/'ESC' to ignore."

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18076 6f19259b-4bc3-4df7-8a09-765794883524