Extend OmniboxOnFocusSuggestions flag until M90.

The flag expired with M86 and does not show in
most recent Canary builds of Chrome.

Change-Id: If1cb6a2be57bd6f8e7c8027f334da48afd482897
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2372741Reviewed-by: Ted Choc <tedchoc@chromium.org>
Commit-Queue: Tomasz Wiszkowski <ender@google.com>
Cr-Commit-Position: refs/heads/master@{#801240}

chrome/browser/flag-metadata.json

@@ -3358,7 +3358,7 @@
   {
     "name": "omnibox-on-focus-suggestions",
     "owners": [ "chrome-omnibox-team@google.com" ],
-    "expiry_milestone": 86
+    "expiry_milestone": 90
   },
   {
     "name": "omnibox-on-focus-suggestions-contextual-web",