Initialize palette field in icon manager

This doesn't make a difference right now but in generall it is better to
have the field initialized from the beginning (in accordance to the palette
that is determined anyway for making ForkAwesome icons).

syncthingmodel/syncthingicons.cpp

@@ -340,10 +340,10 @@ ForkAwesomeIcons::ForkAwesomeIcons(QtForkAwesome::Renderer &renderer, const QCol
 }
 
 IconManager::IconManager(const QPalette *palette)
-    : m_statusIcons()
+    : m_palette(palette ? *palette : QGuiApplication::palette())
+    , m_statusIcons()
     , m_trayIcons(m_statusIcons)
-    , m_commonForkAwesomeIcons(
-          m_forkAwesomeRenderer, (palette ? *palette : QGuiApplication::palette()).color(QPalette::Normal, QPalette::Text), QSize(64, 64))
+    , m_commonForkAwesomeIcons(m_forkAwesomeRenderer, m_palette.color(QPalette::Normal, QPalette::Text), QSize(64, 64))
     , m_distinguishTrayIcons(false)
 {
     m_forkAwesomeRenderer.warnIfInvalid();

syncthingmodel/syncthingicons.h

@@ -185,11 +185,11 @@ public Q_SLOTS:
 private:
     explicit IconManager(const QPalette *palette = nullptr);
 
+    QPalette m_palette;
     StatusIcons m_statusIcons;
     StatusIcons m_trayIcons;
     QtForkAwesome::Renderer m_forkAwesomeRenderer;
     ForkAwesomeIcons m_commonForkAwesomeIcons;
-    QPalette m_palette;
     std::optional<StatusIconSettings> m_paletteBasedSettingsForStatus;
     std::optional<StatusIconSettings> m_paletteBasedSettingsForTray;
     bool m_distinguishTrayIcons;