Update expiration milestones for Launcher and Shelf flags

Bug: none
Test: none
Change-Id: Iee2fc67f7e9c25c3a8f745b0c316acdaf16b28ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1859680
Commit-Queue: Vladislav Kaznacheev <kaznacheev@chromium.org>
Reviewed-by: Matthew Mourgos <mmourgos@chromium.org>
Reviewed-by: Manu Cornet <manucornet@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#706167}

chrome/browser/flag-metadata.json

@@ -871,12 +871,12 @@
   {
     "name": "enable-app-data-search",
     "owners": [ "jennyz", "kaznacheev" ],
-    "expiry_milestone": 78
+    "expiry_milestone": 86
   },
   {
     "name": "enable-app-grid-ghost",
     "owners": [ "mmourgos" ],
-    "expiry_milestone": 78
+    "expiry_milestone": 82
   },
   {
     "name": "enable-app-list-search-autocomplete",
@@ -1493,7 +1493,7 @@
   {
     "name": "enable-notification-indicator",
     "owners": [ "newcomer" ],
-    "expiry_milestone": 78
+    "expiry_milestone": 83
   },
   {
     "name": "enable-ntp-remote-suggestions",
@@ -1543,7 +1543,7 @@
   {
     "name": "enable-play-store-search",
     "owners": [ "jennyz", "kaznacheev" ],
-    "expiry_milestone": 78
+    "expiry_milestone": 83
   },
   {
     "name" : "enable-pointer-lock-options",
@@ -3042,7 +3042,7 @@
   {
     "name": "shelf-hover-previews",
     "owners": [ "manucornet" ],
-    "expiry_milestone": 77
+    "expiry_milestone": 84
   },
   {
     "name": "shelf-scrollable",