[LYN-4938] Prism: Paths in Engine settings page do not use consistent slashes (#1721)

* Corrected focus for form line edit widgets.
* Consistent slash usage for folder browse edit widgets.

Signed-off-by: Benjamin Jillich <jillich@amazon.com>

Code/Tools/ProjectManager/Source/FormLineEditWidget.h

@@ -15,6 +15,7 @@ QT_FORWARD_DECLARE_CLASS(QLineEdit)
 QT_FORWARD_DECLARE_CLASS(QLabel)
 QT_FORWARD_DECLARE_CLASS(QFrame)
 QT_FORWARD_DECLARE_CLASS(QHBoxLayout)
+QT_FORWARD_DECLARE_CLASS(QMouseEvent)
 
 namespace AzQtComponents
 {
@@ -39,6 +40,8 @@ namespace O3DE::ProjectManager
         //! Returns a pointer to the underlying LineEdit.
         QLineEdit* lineEdit() const;
 
+        virtual void setText(const QString& text);
+
     protected:
         QLabel* m_errorLabel = nullptr;
         QFrame* m_frame = nullptr;
@@ -51,6 +54,8 @@ namespace O3DE::ProjectManager
         void onFocusOut();
 
     private:
+        void mousePressEvent(QMouseEvent* event) override;
+
         void refreshStyle();
     };
 } // namespace O3DE::ProjectManager