MdeModulePkg/UefiBootManagerLib: Skip the DNS device path node check.

MdeModulePkg/UefiBootManagerLib: Skip the DNS device path node check.

After HTTP boot successfully in home mode, the HTTP device path will be
updated accordingly. So, the new device path may be appended with a DNS
device path node. When executing home mode boot again, the original HTTP
device path will mismatch with the new updated one, which will cause the
HTTP boot failure. So, we need update the current match algorithm to match
the correct FilePath. Since the DNS device path is an optional, we can skip
it check.

This patch is to fix above issue.

Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Ye Ting <ting.ye@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Wu Jiaxin <jiaxin.wu@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>