Initial improvements to fix viewport icon selection and draw order (#6284)

* wip fixes for entity viewport icons displaying in the correct order and handling selection correctly

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

* add additional comment about z value

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

* move manual sorting and some small tidy-up

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

* update comment

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

* updates following initial round of PR feedback

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

* additional changes to support tests for entity icon intersection

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

* add support to enable/disable icons separately from helpers

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

* final tests added and small tidy-up to display EntityId correctly

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

* update some manipulator test framework calls after utility functions were moved

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

* fix for implicit cast

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

* move icon scale values to AZ_CVARS

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

* fix failing tests caught in AR and update some naming conventions for tests

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

* update naming convention for members of ProjectedViewportRay

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

* update other references to ProjectedViewportRay

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

* update more references to ProjectedViewportRay change

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

* update menus for python tests

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

Gems/WhiteBox/Code/Source/EditorWhiteBoxComponent.cpp

@@ -720,7 +720,6 @@ namespace WhiteBox
         // must have at least one triangle
         if (m_faces->empty())
         {
-            distance = std::numeric_limits<float>::max();
             return false;
         }
 
@@ -735,7 +734,6 @@ namespace WhiteBox
         const AZ::Vector3 localRayEnd = localRayOrigin + localRayDirection * rayLength;
 
         bool intersection = false;
-        distance = std::numeric_limits<float>::max();
         for (const auto& face : m_faces.value())
         {
             float t;