[ios] Add Flag Ownership for livvielin

iOS flag owners were asked to claim ownership and state an expiry in
this announcement email:
https://groups.google.com/a/google.com/g/bling-team/c/7YC_3l6yEzo/m/1-iZg1fPAAAJ

This is one of several CLs that adds iOS flag ownership information into
flag-metadata.json.

Bug: 1058614
Change-Id: I4b21639bcbc1e78e0417e75614c0232f700ffe71
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2094239Reviewed-by: Livvie Lin <livvielin@chromium.org>
Reviewed-by: edchin <edchin@chromium.org>
Commit-Queue: edchin <edchin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#748283}

chrome/browser/flag-metadata.json

@@ -3387,6 +3387,11 @@
     "owners": [ "jamescook", "cros-system-services@google.com" ],
     "expiry_milestone": 84
   },
+  {
+    "name": "ssl-committed-interstitials",
+    "owners": [ "livvielin" ],
+    "expiry_milestone": 84
+  },
   {
     "name": "stop-in-background",
     "owners": [ "chrome-catan@google.com" ],