fix crash & empty nickname bug

app/src/main/java/org/thoughtcrime/securesms/conversation/ConversationActivity.java

@@ -417,7 +417,9 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
           });
           String nickname = DatabaseFactory.getStorage(this).getDisplayName(getRecipient().getAddress().serialize());
           titleTextView.setText(nickname);
-          titleTextView.setSelection(nickname.length());
+          if (nickname != null) {
+            titleTextView.setSelection(nickname.length());
+          }
           imm.showSoftInput(v, 0);
           cancelButtonContainer.setVisibility(View.VISIBLE);
         }

app/src/main/java/org/thoughtcrime/securesms/sskenvironment/ProfileManager.kt

@@ -21,6 +21,7 @@ class ProfileManager: SSKEnvironment.ProfileManagerProtocol {
     override fun setProfileName(context: Context, recipient: Recipient, profileName: String) {
         val database = DatabaseFactory.getRecipientDatabase(context)
         database.setProfileName(recipient, profileName)
+        recipient.notifyListeners()
     }
 
     override fun setProfilePictureURL(context: Context, recipient: Recipient, profilePictureURL: String) {

libsession/src/main/java/org/session/libsession/messaging/threads/recipients/Recipient.java

@@ -288,7 +288,7 @@ public class Recipient implements RecipientModifiedListener {
   public synchronized @Nullable String getName() {
 
     String displayName = MessagingModuleConfiguration.shared.getStorage().getDisplayName(this.address.toString());
-    if (displayName != null) { return displayName; }
+    if (displayName != null && !displayName.isEmpty()) { return displayName; }
 
     if (this.name == null && isMmsGroupRecipient()) {
       List<String> names = new LinkedList<>();