Add support URL for usernames.

app/src/main/java/org/thoughtcrime/securesms/profiles/manage/UsernameEducationFragment.kt

@@ -10,6 +10,7 @@ import org.thoughtcrime.securesms.databinding.UsernameEducationFragmentBinding
 import org.thoughtcrime.securesms.dependencies.ApplicationDependencies
 import org.thoughtcrime.securesms.keyvalue.SignalStore
 import org.thoughtcrime.securesms.megaphone.Megaphones
+import org.thoughtcrime.securesms.util.CommunicationActions
 import org.thoughtcrime.securesms.util.navigation.safeNavigate
 
 /**
@@ -25,7 +26,7 @@ class UsernameEducationFragment : Fragment(R.layout.username_education_fragment)
     }
 
     binding.usernameEducationLearnMore.setOnClickListener {
-      // TODO [alex] -- Launch "Learn More" page.
+      CommunicationActions.openBrowserLink(requireContext(), getString(R.string.username_support_url))
     }
 
     binding.continueButton.setOnClickListener {

app/src/main/res/values/strings.xml

@@ -14,6 +14,7 @@
     <string name="sms_export_url" translatable="false">https://support.signal.org/hc/articles/360007321171</string>
     <string name="signal_me_username_url" translatable="false">https://signal.me/#u/%1$s</string>
     <string name="signal_me_username_url_no_scheme" translatable="false">signal.me/#u/%1$s</string>
+    <string name="username_support_url" translatable="false">https://support.signal.org/hc/articles/5389476324250</string>
 
     <string name="yes">Yes</string>
     <string name="no">No</string>