[COOP] Push flag expiration to M88.

Without this, Canary users won't see the chrome://flags

Bug: 1059303
Change-Id: I30874282ac3be605198b8e44d2e831e05289d502
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2377490
Auto-Submit: Arthur Sonzogni <arthursonzogni@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Commit-Queue: Camille Lamy <clamy@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#801756}

chrome/browser/flag-metadata.json

@@ -669,7 +669,7 @@
   {
     "name": "cross-origin-isolated",
     "owners": [ "ahemery", "arthursonzogni", "clamy", "pmeuleman" ],
-    "expiry_milestone": 86
+    "expiry_milestone": 88
   },
   {
     "name": "cross-origin-opener-policy",
@@ -679,12 +679,12 @@
   {
     "name": "cross-origin-opener-policy-access-reporting",
     "owners": [ "ahemery", "arthursonzogni", "clamy", "pmeuleman" ],
-    "expiry_milestone": 86
+    "expiry_milestone": 88
   },
   {
     "name": "cross-origin-opener-policy-reporting",
     "owners": [ "ahemery", "arthursonzogni", "clamy", "pmeuleman" ],
-    "expiry_milestone": 86
+    "expiry_milestone": 88
   },
   {
     "name": "crostini-disk-resizing",