[Fix] (MG_Util): GL_FLOAT_32_UNSIGNED_INT_24_8_REV is 8 bytes per pixel

The packed-type size table listed the D32F+S8 client format at 4 bytes,
so every GL_DEPTH32F_STENCIL8 upload copied only half its client data -
the top half of such textures stayed zero (packed_depth_stencil
verify_read_pixels/clear_buffer.depth32f_stencil8 now pass).

MobileGL/MG_Util/Metrics/TextureMetrics.cpp

@@ -255,8 +255,10 @@ namespace MobileGL {
             case TexturePixelDataType::UnsignedInt101111Rev:
             case TexturePixelDataType::UnsignedInt5999Rev:
             case TexturePixelDataType::UnsignedInt248:
-            case TexturePixelDataType::Float32UnsignedInt248Rev:
                 return 4;
+            case TexturePixelDataType::Float32UnsignedInt248Rev:
+                // A 32-bit float depth word followed by a 32-bit word holding stencil.
+                return 8;
             default:
                 return 0;
             }