fix: default to NTLM v2 in network service for POSIX platforms

NTLM always defaults to NTLM v2 at the //net layer for quite
sometime now https://crbug.com/22532.

Change-Id: I4ea2dedc10c63a7c4e00101c0acc6d8a713c5054
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2222116
Auto-Submit: Deepak Mohan <hop2deep@gmail.com>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773809}

services/network/public/mojom/network_service.mojom

@@ -152,7 +152,7 @@ struct HttpAuthDynamicParams {
   bool enable_negotiate_port = true;
 
   // Whether NTLM V2 is enabled on POSIX platforms. No effect elsewhere.
-  bool ntlm_v2_enabled = false;
+  bool ntlm_v2_enabled = true;
 
   // The AccountManager AccountManagerget.AccountsByTypeAndFeatures on Android
   // when using Negotiate authentication.