fix(UI): fix own status message not being properly displayed in tooltip

This causes a slight regression where own status can become quite huge
when user sets e.g. 120 newlines between first and last character of the
status message.

Given that this fixes a problem with incorrect (broken) formatting of
display of own status messages, the slight regression is insignificant.

There is also a Qt bug involved that causes formatting to be broken if
text contains "HTML" tags.
https://bugreports.qt.io/browse/QTBUG-57477

Used workaround requires using additional HTML to preserve newlines even
if HTML is a part of the status message.

Related to #935.

src/widget/widget.cpp

@@ -976,7 +976,11 @@ void Widget::setStatusMessage(const QString& statusMessage)
     else
     {
         ui->statusLabel->setText(statusMessage);
-        ui->statusLabel->setToolTip(Qt::convertFromPlainText(statusMessage, Qt::WhiteSpaceNormal)); // for overlength messsages
+        // escape HTML from tooltips and preserve newlines
+        // TODO: move newspace preservance to a generic function
+        ui->statusLabel->setToolTip("<p style='white-space:pre'>" +
+                                    statusMessage.toHtmlEscaped() +
+                                    "</p>");
     }
 }