[Password change] Extend password change flags expiry_milestone

Bug: 1086109
Change-Id: I8b5d54afb531993436b14be1c5715d0869f58c70
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2452769
Commit-Queue: Milica Selakovic <selakovic@google.com>
Commit-Queue: Maxim Kolosovskiy  <kolos@chromium.org>
Reviewed-by: Maxim Kolosovskiy  <kolos@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814232}

chrome/browser/flag-metadata.json

@@ -3655,7 +3655,7 @@
   {
     "name": "password-change-in-settings",
     "owners": [ "kolos" ],
-    "expiry_milestone": 89
+    "expiry_milestone": 90
   },
   {
     "name": "password-change-support",
@@ -3670,7 +3670,7 @@
   {
     "name": "password-scripts-fetching",
     "owners": [ "kolos" ],
-    "expiry_milestone": 89
+    "expiry_milestone": 90
   },
   {
     "name": "PasswordImport",