Quick Answers: Extend flag expiration

Extend the expiry milestone of Quick Answers related feature flag.

Bug: None
Test: Locally build and test
Change-Id: I2df16ed1037d5f333cf864c1d697b0ec8c636587
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2419752
Auto-Submit: Yue Li <updowndota@chromium.org>
Commit-Queue: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#808991}

chrome/browser/flag-metadata.json

@@ -1975,17 +1975,17 @@
   {
     "name": "enable-quick-answers",
     "owners": [ "croissant-eng" ],
-    "expiry_milestone": 86
+    "expiry_milestone": 90
   },
   {
     "name": "enable-quick-answers-rich-ui",
     "owners": [ "croissant-eng" ],
-    "expiry_milestone": 86
+    "expiry_milestone": 90
   },
   {
     "name": "enable-quick-answers-text-annotator",
     "owners": [ "croissant-eng" ],
-    "expiry_milestone": 88
+    "expiry_milestone": 90
   },
   {
     "name": "enable-quick-answers-translation",