yuzu/configuration: Make slots private where applicable

These slots are only ever attached to event handling mechanisms within
the class itself, they're never used externally. Because of this, we can
make the functions private.

This also removes redundant usages of the private access specifier.

src/citra_qt/configuration/configure_audio.h

@@ -22,10 +22,9 @@ public:
     void retranslateUi();
     void setConfiguration();
 
-public slots:
+private:
     void updateAudioDevices(int sink_index);
 
-private:
     void setOutputSinkFromSinkID();
     void setAudioDeviceFromDeviceID();
     void setVolumeIndicatorText(int percentage);

src/citra_qt/configuration/configure_debug.h

@@ -22,6 +22,5 @@ public:
     void retranslateUi();
     void setConfiguration();
 
-private:
     std::unique_ptr<Ui::ConfigureDebug> ui;
 };

src/citra_qt/configuration/configure_dialog.h

@@ -34,6 +34,5 @@ private:
     void setConfiguration();
     void retranslateUi();
 
-private:
     std::unique_ptr<Ui::ConfigureDialog> ui;
 };

src/citra_qt/configuration/configure_graphics.h

@@ -22,7 +22,6 @@ public:
     void retranslateUi();
     void setConfiguration();
 
-private:
     std::unique_ptr<Ui::ConfigureGraphics> ui;
     QColor bg_color;
 };

src/citra_qt/configuration/configure_web.h

@@ -23,13 +23,12 @@ public:
     void retranslateUi();
     void setConfiguration();
 
-public slots:
+private:
     void RefreshTelemetryID();
     void OnLoginChanged();
     void VerifyLogin();
     void OnLoginVerified();
 
-private:
     bool user_verified = true;
     QFutureWatcher<bool> verify_watcher;