NetworkPkg/NetworkPkg.ci.yaml: Add configuration for LicenseCheck

Add configuration IgnoreFiles for package config files.
So users can rely on this to skip license conflict for
some generated files.

Cc: Maciej Rabeda <maciej.rabeda@linux.intel.com>
Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>