Add tests for planar manipulator draw when dealing with scaling (#6164)

* add support to add a custom debug display request interface for manipulator test framework

Signed-off-by: Tom Hulton-Harrop <82228511+hultonha@users.noreply.github.com>

* wip changes to support tests for manipulator view drawing

Signed-off-by: Tom Hulton-Harrop <82228511+hultonha@users.noreply.github.com>

* add test for planar manipulator draw when dealing with scaling

Signed-off-by: Tom Hulton-Harrop <82228511+hultonha@users.noreply.github.com>

* additional comments for added context

Signed-off-by: Tom Hulton-Harrop <82228511+hultonha@users.noreply.github.com>

* small updates/fixes after PR feedback

Signed-off-by: Tom Hulton-Harrop <82228511+hultonha@users.noreply.github.com>

* fix for missing NullDebugDisplayRequests

Signed-off-by: Tom Hulton-Harrop <82228511+hultonha@users.noreply.github.com>

Code/Framework/AzToolsFramework/AzToolsFramework/UnitTest/AzToolsFrameworkTestHelpers.h

@@ -15,12 +15,14 @@
 #include <AzCore/Slice/SliceComponent.h>
 #include <AzCore/std/containers/unordered_map.h>
 #include <AzCore/std/parallel/binary_semaphore.h>
+#include <AzCore/std/smart_ptr/make_shared.h>
 #include <AzCore/std/smart_ptr/unique_ptr.h>
 #include <AzCore/UnitTest/TestTypes.h>
 #include <AzCore/UserSettings/UserSettingsComponent.h>
 #include <AzTest/AzTest.h>
 #include <AZTestShared/Math/MathTestHelpers.h>
 #include <AZTestShared/Utils/Utils.h>
+#include <AzFramework/UnitTest/TestDebugDisplayRequests.h>
 #include <AzToolsFramework/API/ToolsApplicationAPI.h>
 #include <AzToolsFramework/API/ViewportEditorModeTrackerInterface.h>
 #include <AzToolsFramework/API/ViewportEditorModeTrackerNotificationBus.h>
@@ -235,6 +237,13 @@ namespace UnitTest
             return toolsApp;
         }
 
+        //! It is possible to override this in classes deriving from ToolsApplicationFixture to provide alternate
+        //! implementations of the DebugDisplayRequests interface (e.g. TestDebugDisplayRequests).
+        virtual AZStd::shared_ptr<AzFramework::DebugDisplayRequests> CreateDebugDisplayRequests()
+        {
+            return AZStd::make_shared<NullDebugDisplayRequests>();
+        }
+
     protected:
         TestEditorActions m_editorActions;
         ToolsApplicationMessageHandler m_messageHandler; // used to suppress trace messages in test output