Prevent logging into the same account twice

Check if an account is already logged in before allow the login process to continue.

BUG:459603

src/login.cpp

@@ -3,6 +3,12 @@
 
 #include "login.h"
 
+#ifdef QUOTIENT_07
+#include <accountregistry.h>
+#else
+#include "neochataccountregistry.h"
+#endif
+
 #include <connection.h>
 #include <qt_connection_util.h>
 
@@ -39,6 +45,12 @@ void Login::init()
             return;
         }
 
+        m_isLoggedIn = AccountRegistry::instance().isLoggedIn(m_matrixId);
+        Q_EMIT isLoggedInChanged();
+        if (m_isLoggedIn) {
+            return;
+        }
+
         m_testing = true;
         Q_EMIT testingChanged();
         if (!m_connection) {
@@ -181,3 +193,8 @@ bool Login::isLoggingIn() const
 {
     return m_isLoggingIn;
 }
+
+bool Login::isLoggedIn() const
+{
+    return m_isLoggedIn;
+}