Update fieldtrial_testing_config.json for the privacy settings trials

1. Extend the privacy-settings-redesign trial to M84, as we still need
it beyond M82.
2. Replace chrome-friendly-settings with
chrome-friendly-settings@google.com. Not specifying the email domain
assumes @chromium.org address, but this mailinglist uses the @google.com
domain.
3. Replace chrome-privacy-core@google.com with
chrome-friendly-settings@chromium.org, which is a better fit.

Bug: 1032584
Change-Id: I1b8db25bd4bbc584539804b84ccac6540d386715
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2066837Reviewed-by: Huanzhong Huang <huanzhong@chromium.org>
Commit-Queue: Martin Šrámek <msramek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743514}

chrome/browser/flag-metadata.json

@@ -2414,12 +2414,12 @@
   },
   {
     "name": "happiness-tracking-surveys-for-desktop-settings",
-    "owners": [ "msramek", "chrome-friendly-settings" ],
+    "owners": [ "msramek", "chrome-friendly-settings@google.com" ],
     "expiry_milestone": 86
   },
   {
     "name": "happiness-tracking-surveys-for-desktop-settings-privacy",
-    "owners": [ "msramek", "chrome-friendly-settings" ],
+    "owners": [ "msramek", "chrome-friendly-settings@google.com" ],
     "expiry_milestone": 86
   },
   {
@@ -3128,8 +3128,8 @@
   {
     "name": "privacy-settings-redesign",
     "owners": ["harrisonsean", "msramek",
-      "chrome-privacy-core@google.com"],
-    "expiry_milestone": 82
+      "chrome-friendly-settings@google.com"],
+    "expiry_milestone": 84
   },
   {
     "name": "proactive-tab-freeze",