Prolong Password Manager flags.

Change-Id: I565fc449a2ba850c0b5aa1e552e0f01a6731e1a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1917515
Auto-Submit: Vadym Doroshenko <dvadym@chromium.org>
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Commit-Queue: Vasilii Sukhanov <vasilii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715648}

chrome/browser/flag-metadata.json

@@ -3001,7 +3001,7 @@
   {
     "name": "password-leak-detection",
     "owners": [ "jdoerrie", "vasilii" ],
-    "expiry_milestone": 80
+    "expiry_milestone": 81
   },
   {
     "name": "password-manager-onboarding-android",
@@ -3011,7 +3011,7 @@
   {
     "name": "PasswordImport",
     "owners": [ "vasilii" ],
-    "expiry_milestone": 76
+    "expiry_milestone": 88
   },
   {
     "name": "passwords-account-storage",
@@ -3606,7 +3606,7 @@
   {
     "name": "username-first-flow",
     "owners": [ "dvadym" ],
-    "expiry_milestone": 80
+    "expiry_milestone": 84
   },
   {
     "name": "wake-on-wifi-packet",