NetworkPkg:Fix the issue that cannot parse ipv6 address correctly.

NetworkPkg:Fix the issue that cannot parse ipv6 address correctly.

If there is a ipv6 expressed url, the NetLibAsciiStrToIp6 cannot get the Ipv6
address from the host name, because the host name contains left and right
bracket which cannot be used to configure the Tcp6 connection.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Zhang Lubo <lubo.zhang@intel.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Wu Jiaxin <jiaxin.wu@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18745 6f19259b-4bc3-4df7-8a09-765794883524