fixed a code smell

Author: markelov208

applications/GeoMechanicsApplication/custom_utilities/constitutive_law_utilities.cpp

@@ -207,8 +207,8 @@ double ConstitutiveLawUtilities::GetUndrainedPoissonsRatio(const Properties& rPr
             << "Non-physical values: denominator < epsilon." << std::endl;
         result = (3.0 * poissons_ratio + biot_coefficient * skempton_b * (1.0 - 2.0 * poissons_ratio)) / denominator;
     }
-    constexpr auto max_poisson_ratio = 0.495;
-    if (result > max_poisson_ratio) {
+
+    if (constexpr auto max_poisson_ratio = 0.495; result > max_poisson_ratio) {
         KRATOS_WARNING("Clamping undrained Poisson ratio from ")
             << result << " to " << max_poisson_ratio << "." << std::endl;
         return max_poisson_ratio;