plugin_vm: extending expiry for microphone and camera flags

Bug: 1106149
Change-Id: If45d22a6f86fec21a3b666ff06bde258b2304ba1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2467036
Auto-Submit: Daniel Ng <danielng@google.com>
Reviewed-by: Jason Lin <lxj@google.com>
Commit-Queue: Jason Lin <lxj@google.com>
Cr-Commit-Position: refs/heads/master@{#816414}

chrome/browser/flag-metadata.json

@@ -3720,12 +3720,12 @@
   {
     "name": "pluginvm-show-camera-permissions",
     "owners": [ "danielng@google.com", "lxj@google.com" ],
-    "expiry_milestone": 87
+    "expiry_milestone": 90
   },
   {
     "name": "pluginvm-show-microphone-permissions",
     "owners": [ "dtor", "lxj@google.com" ],
-    "expiry_milestone": 87
+    "expiry_milestone": 90
   },
   {
     "name": "pointer-support",