[Passwords] Bump Expiry Milestone of FillOnAccountSelect Flag

TBR=jdoerrie@chromium.org

Bug: NONE
Change-Id: I1ac9128815d5f59127c6618227ff3ac42d6f7193
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1583737Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654493}

chrome/browser/flag-metadata.json

@@ -2008,7 +2008,7 @@
   {
     "name": "fill-on-account-select",
     "owners": [ "jdoerrie" ],
-    "expiry_milestone": 76
+    "expiry_milestone": 80
   },
   {
     "name": "fill-on-account-select-http",