Previous posts: inject in the unified profiles iframe

We previously added support of the previous posts links for unified
profiles, but unfortunately we forgot to change the manifest so it is
also injected when the profile is inside an iframe in the Community
Console. This change fixes this.

Change-Id: I0d2c9424dede33a9aa79c6f7169a23e76c4b55d5
diff --git a/templates/manifest.gjson b/templates/manifest.gjson
index eaba14e..6f25516 100644
--- a/templates/manifest.gjson
+++ b/templates/manifest.gjson
@@ -43,6 +43,7 @@
     },
     {
       "matches": ["https://support.google.com/*/profile/*", "https://support.google.com/profile/*"],
+      "all_frames": true,
       "js": ["common/content_scripts.js", "content_scripts/profile_inject.js"],
       "css": ["common/forum.css"]
     }