Update HolographicButtonContentCageProximity's alpha to avoid dark color in MRC videos

Author: cre8ivepark

Assets/MRTK/SDK/Features/UX/Interactable/Materials/HolographicButtonContentCageProximity.mat

@@ -113,6 +113,7 @@ Material:
     - _EnableLocalSpaceTriplanarMapping: 0
     - _EnableNormalMap: 0
     - _EnableProximityLightColorOverride: 0
+    - _EnableSSAA: 0
     - _EnableTriplanarMapping: 0
     - _EnvironmentColorIntensity: 0.5
     - _EnvironmentColorThreshold: 1.5
@@ -136,6 +137,7 @@ Material:
     - _IridescenceIntensity: 0.5
     - _IridescenceThreshold: 0.05
     - _Metallic: 0
+    - _MipmapBias: -2
     - _Mode: 4
     - _NearLightFade: 1
     - _NearPlaneFade: 1
@@ -177,7 +179,7 @@ Material:
     - _ClipPlane: {r: 0, g: 1, b: 0, a: 0}
     - _ClippingBorderColor: {r: 1, g: 0.2, b: 0, a: 1}
     - _ClippingPlaneBorderColor: {r: 1, g: 0.2, b: 0, a: 1}
-    - _Color: {r: 0, g: 0, b: 0, a: 1}
+    - _Color: {r: 0, g: 0, b: 0, a: 0}
     - _EmissionColor: {r: 0, g: 0, b: 0, a: 1}
     - _EmissiveColor: {r: 0, g: 0, b: 0, a: 1}
     - _EnvironmentColorX: {r: 1, g: 0, b: 0, a: 1}