Bumping language detection flag expiry to M89

We are aiming for feature launch in M89.

Change-Id: I592d5f4fadb095c38870d46dfcf48d3206b8c4c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2515803Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Commit-Queue: Chris Hall <chrishall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824334}

chrome/browser/flag-metadata.json

@@ -1495,12 +1495,12 @@
   {
     "name": "enable-experimental-accessibility-language-detection",
     "owners": [ "chrishall", "//ui/accessibility/OWNERS" ],
-    "expiry_milestone": 87
+    "expiry_milestone": 89
   },
   {
     "name": "enable-experimental-accessibility-language-detection-dynamic",
     "owners": [ "chrishall", "//ui/accessibility/OWNERS" ],
-    "expiry_milestone": 87
+    "expiry_milestone": 89
   },
   {
     "name": "enable-experimental-accessibility-switch-access-text",