Update form-controls-dark-mode flag expiry-milestone

Update form-controls-dark-mode flag expiry-milestone


Tbr: masonfreed@chromium.org
Bug: 929098
Change-Id: I5934653aaf0514cf7c4172a4dccdc34bdaee383b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2532581
Commit-Queue: Yu Han <yuzhehan@chromium.org>
Reviewed-by: Yu Han <yuzhehan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#826603}

chrome/browser/flag-metadata.json

@@ -2700,7 +2700,7 @@
   {
     "name": "form-controls-dark-mode",
     "owners": [ "sasebree@microsoft.com", "masonfreed", "yuzhehan", "//third_party/blink/renderer/core/OWNERS" ],
-    "expiry_milestone": 88
+    "expiry_milestone": 90
   },
   {
     "name": "form-controls-refresh",