[Client] Extract sendPrivateMessage() to fix invite message draft overwrite

sendInviteMessage() was calling sayEdit->setText(text) then sendMessage(),
which overwrites any text the user had typed.  Extract the command-building
and sending logic into a new sendPrivateMessage(const QString &text) method
that takes the text directly.  sendMessage() now calls it after its guards
and clears sayEdit; sendInviteMessage() calls it directly without touching
the input field at all.

Took 33 minutes

cockatrice/src/interface/widgets/tabs/tab_message.cpp

@@ -96,6 +96,18 @@ void TabMessage::closeEvent(QCloseEvent *event)
     event->accept();
 }
 
+void TabMessage::sendPrivateMessage(const QString &text)
+{
+    Command_Message cmd;
+    cmd.set_user_name(otherUserInfo->name());
+    cmd.set_message(text.toStdString());
+
+    PendingCommand *pend = client->prepareSessionCommand(cmd);
+    pend->setExtraData(text);
+    connect(pend, &PendingCommand::finished, this, &TabMessage::messageSent);
+    client->sendCommand(pend);
+}
+
 void TabMessage::sendMessage()
 {
     if (sayEdit->text().isEmpty()) {
@@ -103,28 +115,21 @@ void TabMessage::sendMessage()
     }
 
     if (!userOnline) {
-        // Keep the draft: the user may be back momentarily, and the typed text
-        // should not be lost to a transient offline spell.
         notifyUserOffline();
         return;
     }
 
-    Command_Message cmd;
+    sendPrivateMessage(sayEdit->text());
-    cmd.set_user_name(otherUserInfo->name());
-    cmd.set_message(sayEdit->text().toStdString());
-
-    PendingCommand *pend = client->prepareSessionCommand(cmd);
-    pend->setExtraData(sayEdit->text());
-    connect(pend, &PendingCommand::finished, this, &TabMessage::messageSent);
-    client->sendCommand(pend);
-
     sayEdit->clear();
 }
 
 void TabMessage::sendInviteMessage(const QString &text)
 {
-    sayEdit->setText(text);
+    if (!userOnline) {
-    sendMessage();
+        notifyUserOffline();
+        return;
+    }
+    sendPrivateMessage(text);
 }
 
 void TabMessage::messageSent(const Response &response,

cockatrice/src/interface/widgets/tabs/tab_message.h

@@ -67,6 +67,7 @@ public:
     void sendInviteMessage(const QString &text);
 
 private:
+    void sendPrivateMessage(const QString &text);
     bool shouldShowSystemPopup(const Event_UserMessage &event);
     void showSystemPopup(const Event_UserMessage &event);
     void notifyUserOffline();