[CrOS Cellular] Extend expiry to M95 for updated_cellular_activation_ui.

- This feature was never launched and the flag expired in M89.
Extending expiry so that this flag can be re-used for a
new unified cellular setup UI.
- Updated team owner to cros-connectivity

Bug: 1093185
Change-Id: I6edea8d789edf3d56c3142e2884ef11406ab4ef6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2638358Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Nnamdi Theodore Johnson-kanu <tjohnsonkanu@google.com>
Cr-Commit-Position: refs/heads/master@{#844946}

chrome/browser/flag-metadata.json

@@ -4863,8 +4863,8 @@
   },
   {
     "name": "updated_cellular_activation_ui",
-    "owners": [ "azeemarshad", "khorimoto", "vecore", "cros-system-services@google.com" ],
-    "expiry_milestone": 89
+    "owners": [ "azeemarshad", "khorimoto", "vecore", "cros-connectivity@google.com" ],
+    "expiry_milestone": 95
   },
   {
     "name": "url-blocklist-ios",