FontAccess: Bump flag expiry to M89

Bumping the expiry for the #font-access flag to M89.
We are aiming to go to Origin Trial in M86. Adding 3 milestones brings
us to M89.

Bug: 1100580
Change-Id: I238851a6b30a319fb7a90c27c0dc51d1b2020eb3
Fixes: 1100580
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2274243
Commit-Queue: Olivier Yiptong <oyiptong@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#783741}

chrome/browser/flag-metadata.json

@@ -2620,7 +2620,7 @@
   {
     "name": "font-access",
     "owners": [ "cmp", "oyiptong" ],
-    "expiry_milestone": 85
+    "expiry_milestone": 89
   },
   {
     "name": "force-color-profile",