Focus issue in editor settings menu #3921 (#6296)

* Changes to fix DCO

Signed-off-by: John Jones-Steele <82226755+jjjoness@users.noreply.github.com>

* Moved the keyEvent to a helper function for ease of testing

Signed-off-by: John Jones-Steele <82226755+jjjoness@users.noreply.github.com>

* Split definition and declaration of WidgetHandleKeyPressEvent

Signed-off-by: John Jones-Steele <82226755+jjjoness@users.noreply.github.com>

Code/Editor/EditorPreferencesDialog.h

@@ -19,6 +19,8 @@ namespace Ui
 
 class EditorPreferencesTreeWidgetItem;
 
+void WidgetHandleKeyPressEvent(QWidget* widget, QKeyEvent* event);
+
 class EditorPreferencesDialog
     : public QDialog
     , public AzToolsFramework::IPropertyEditorNotify
@@ -36,6 +38,7 @@ public:
 
 protected:
     void showEvent(QShowEvent* event) override;
+    void keyPressEvent(QKeyEvent* event) override;
 
 private:
     void CreateImages();