NetworkPkg/HttpDxe: Destroy the TLS instance when cleaning up the HTTP child

During clean up the HTTP child, all resources used by it should be cleaned. But
currently, TLS instance is not destroyed.

This patch is to fix this issue.

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: Fu Siyuan <siyuan.fu@intel.com>

NetworkPkg/HttpDxe/HttpProto.h

@@ -166,7 +166,8 @@ typedef struct _HTTP_PROTOCOL {
   // Https Support
   //
   BOOLEAN                          UseHttps;
-  
+
+  EFI_SERVICE_BINDING_PROTOCOL     *TlsSb;
   EFI_HANDLE                       TlsChildHandle; /// Tls ChildHandle
   TLS_CONFIG_DATA                  TlsConfigData;
   EFI_TLS_PROTOCOL                 *Tls;