Disable the EnableGetNetworkConnectivityHintAPI feature

While sporadic failures to correctly detect online state are diagnosed
disable the EnableGetNetworkConnectivityHintAPI feature to revert
behavior back to using the older API.

BUG=1489696

(cherry picked from commit e6fea7f)

Change-Id: Ia87287d6c18635c9b40b7f9e1a9d6461524afd70
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4953412
Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1211926}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4953295
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Owners-Override: Daniel Yip <danielyip@google.com>
Commit-Queue: Daniel Yip <danielyip@google.com>
Cr-Commit-Position: refs/branch-heads/5993@{#1355}
Cr-Branched-From: 5113507-refs/heads/main@{#1192594}

net/base/features.cc

@@ -322,9 +322,10 @@ BASE_FEATURE(kPlatformKeyProbeSHA256,
              "PlatformKeyProbeSHA256",
              base::FEATURE_ENABLED_BY_DEFAULT);
 
+// Disabled because of https://crbug.com/1489696.
 BASE_FEATURE(kEnableGetNetworkConnectivityHintAPI,
              "EnableGetNetworkConnectivityHintAPI",
-             base::FEATURE_ENABLED_BY_DEFAULT);
+             base::FEATURE_DISABLED_BY_DEFAULT);
 #endif
 
 // Prefetch to follow normal semantics instead of 5-minute rule