Updated 002_wrinkle_regression_test.material to avoid subsurface scattering artifacts.

Having subsurface scattering into a completely back area is an unrealistic scenario and caused colored artifacts. I changed the material to mask out the black areas from applying SS. Corresponding changes will be made to the expceted screenshot in AtomSampleViewer as well.

Note these artifacts were originally introduced at commit 19638c4697 Fri Jul 2 01:18:09 where SS was fixed to work again where it bad previously been broken and didn't show up in this test case.

Signed-off-by: santorac <55155825+santorac@users.noreply.github.com>

Gems/Atom/TestData/TestData/Materials/SkinTestCases/002_wrinkle_regression_test.material

@@ -33,7 +33,7 @@
         },
         "subsurfaceScattering": {
             "enableSubsurfaceScattering": true,
-            "influenceMap": "Objects/Lucy/Lucy_thickness.tif",
+            "influenceMap": "TestData/Textures/checker8x8_gray_512.png",
             "scatterDistance": 15.0,
             "subsurfaceScatterFactor": 0.4300000071525574,
             "thicknessMap": "Objects/Lucy/Lucy_thickness.tif",
@@ -47,8 +47,7 @@
                 0.3182879388332367,
                 0.16388189792633058,
                 1.0
-            ],
-            "useInfluenceMap": false
+            ]
         },
         "wrinkleLayers": {
             "baseColorMap1": "TestData/Textures/cc0/Lava004_1K_Color.jpg",
@@ -61,4 +60,4 @@
             "normalMap2": "TestData/Textures/TextureHaven/4k_castle_brick_02_red/4k_castle_brick_02_red_normal.png"
         }
     }
-}
+}