fix gles3 shader uniform vec3 error, close #30930

drivers/gles3/rasterizer_storage_gles3.cpp

@@ -2955,7 +2955,9 @@ _FORCE_INLINE_ static void _fill_std140_ubo_empty(ShaderLanguage::DataType type,
 		case ShaderLanguage::TYPE_BVEC3:
 		case ShaderLanguage::TYPE_IVEC3:
 		case ShaderLanguage::TYPE_UVEC3:
-		case ShaderLanguage::TYPE_VEC3:
+		case ShaderLanguage::TYPE_VEC3: {
+			zeromem(data, 12);
+		} break;
 		case ShaderLanguage::TYPE_BVEC4:
 		case ShaderLanguage::TYPE_IVEC4:
 		case ShaderLanguage::TYPE_UVEC4: