Fix hidding the pin/auto-hide icon when side-by-side in floating

An else {} branch was missing.

Also just simplify the code, and call supportsAutoHideButton()
which wasn't being used.

Also removed some bogus updateAutoHideButton() calls from
the CTOR, needs to use singleShot() since the method is virtual,
the derived class isn't constructed yet

src/private/TitleBar.cpp

@@ -39,9 +39,6 @@ TitleBar::TitleBar(Frame *parent)
 
     if (Config::self().flags() & Config::Flag_TitleBarIsFocusable)
         setFocusPolicy(Qt::StrongFocus);
-
-    QTimer::singleShot(0, this, &TitleBar::updateAutoHideButton); // have to wait after the frame is constructed
-    updateAutoHideButton();
 }
 
 TitleBar::TitleBar(FloatingWindow *parent)
@@ -55,7 +52,6 @@ TitleBar::TitleBar(FloatingWindow *parent)
     connect(m_floatingWindow, &FloatingWindow::windowStateChanged, this, &TitleBar::updateMaximizeButton);
     connect(m_floatingWindow, &FloatingWindow::activatedChanged , this, &TitleBar::isFocusedChanged);
     init();
-    updateAutoHideButton(); // always hidden when we're in a FloatingWindow.
 }
 
 void TitleBar::init()
@@ -68,6 +64,8 @@ void TitleBar::init()
     });
 
     updateButtons();
+    QTimer::singleShot(0, this, &TitleBar::updateAutoHideButton); // have to wait after the frame is
+                                                                  // constructed
 }
 
 TitleBar::~TitleBar()

src/private/widgets/TitleBarWidget.cpp

@@ -171,14 +171,10 @@ void TitleBarWidget::updateAutoHideButton()
                 m_autoHideButton->setIcon(factory->iconForButtonType(TitleBarButtonType::UnautoHide, devicePixelRatioF()));
                 m_autoHideButton->setToolTip(tr("Disable auto-hide"));
             }
-
-            m_autoHideButton->setVisible(true);
-        } else {
-            m_autoHideButton->setVisible(false);
         }
-    } else {
-        m_autoHideButton->setVisible(false);
     }
+
+    m_autoHideButton->setVisible(supportsAutoHideButton());
 }
 
 void TitleBarWidget::updateMaximizeButton()