Include enable-pointer-lock-options flag until 92

Pointer Lock Options are launching in 88. The flag should stay for many
more cycles to allow users and developers to turn it off for any reason.

Bug: 982379
Change-Id: I6751b3a400a723540d773e682436890986596e69
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2575052
Commit-Queue: James Hollyer <jameshollyer@chromium.org>
Reviewed-by: Reilly Grant <reillyg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833874}

chrome/browser/flag-metadata.json

@@ -2028,7 +2028,7 @@
   {
     "name": "enable-pointer-lock-options",
     "owners": [ "eirage", "nzolghadr", "input-dev" ],
-    "expiry_milestone": 87
+    "expiry_milestone": 92
   },
   {
     "name": "enable-portals",