MdeModulePkg/SetupBrowserDxe:Follow spec'd way to reconnect driver

MdeModulePkg/SetupBrowserDxe:Follow spec'd way to reconnect driver

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3952

In UEFI spec, it defines reconnect timing that will be activated upon
exiting of the formset or the browser. However, we did't use this kind
of way to check reconnect conditioncode. Code only blocks reconnect if
page is updated dynamically. That's not matched spec'd way. We should
check current formset whether is exiting, then reconnect driver.

Signed-off-by: Walon Li <walon.li@hpe.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>