[Signin][Android] Extend mobile-identity-consitency flag

Extends mobile-identity-consitency flag and updates the list of owners.

Bug: None
Change-Id: I315eb17cf9a23f11221329e0ec2339b42cb58fd5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2237466
Auto-Submit: Boris Sazonov <bsazonov@chromium.org>
Reviewed-by: Alice Wang <aliceywang@chromium.org>
Commit-Queue: Alice Wang <aliceywang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776499}

chrome/browser/flag-metadata.json

@@ -3027,8 +3027,8 @@
   },
   {
     "name": "mobile-identity-consistency",
-    "owners": [ "bsazonov", "droger", "msarda" ],
-    "expiry_milestone": 84
+    "owners": [ "bsazonov", "aliceywang", "msarda" ],
+    "expiry_milestone": 90
   },
   {
     "name": "mouse-subframe-no-implicit-capture",