[PD] make pointers to the UI std::unique_ptr

Same as PR #4293, just for PartDesign

as noted in https://github.com/FreeCAD/FreeCAD/pull/4271#discussion_r554673632
the pointer to the UI should be a unique pointer.

This PR does this for all PartDesign dialogs that don't already use a unique_ptr.

src/Mod/PartDesign/Gui/TaskLinearPatternParameters.cpp

@@ -63,11 +63,11 @@ using namespace Gui;
 /* TRANSLATOR PartDesignGui::TaskLinearPatternParameters */
 
 TaskLinearPatternParameters::TaskLinearPatternParameters(ViewProviderTransformed *TransformedView,QWidget *parent)
-        : TaskTransformedParameters(TransformedView, parent)
+    : TaskTransformedParameters(TransformedView, parent)
+    , ui(new Ui_TaskLinearPatternParameters)
 {
     // we need a separate container widget to add all controls to
     proxy = new QWidget(this);
-    ui = new Ui_TaskLinearPatternParameters();
     ui->setupUi(proxy);
     QMetaObject::connectSlotsByName(this);
 
@@ -83,10 +83,9 @@ TaskLinearPatternParameters::TaskLinearPatternParameters(ViewProviderTransformed
 }
 
 TaskLinearPatternParameters::TaskLinearPatternParameters(TaskMultiTransformParameters *parentTask, QLayout *layout)
-        : TaskTransformedParameters(parentTask)
+        : TaskTransformedParameters(parentTask), ui(new Ui_TaskLinearPatternParameters)
 {
     proxy = new QWidget(parentTask);
-    ui = new Ui_TaskLinearPatternParameters();
     ui->setupUi(proxy);
     connect(ui->buttonOK, SIGNAL(pressed()),
             parentTask, SLOT(onSubTaskButtonOK()));
@@ -415,7 +414,6 @@ TaskLinearPatternParameters::~TaskLinearPatternParameters()
         Base::Console().Error ("%s\n", ex.what () );
     }
 
-    delete ui;
     if (proxy)
         delete proxy;
 }