CSHARP-5409: fix evergreen build errors for atlas tests (#1539)

Author: adelinowona

tests/MongoDB.Driver.Encryption.Tests/SigningRSAESPKCSCallbackTests.cs

@@ -39,11 +39,12 @@ public class SigningRSAESPKCSCallbackTests
             + "9QP1V3SRW0XoD7ez8FpFabp42cmPOxUNk3FK3paQZABLxH5pzCWI9PzIAVfPDrm+sdnbgG7vAnwfL2IMMJSA3aDYGCbF9EgefG+STcpfqq7fQ6f5TBgLFwKBgCd7"
             + "gn1xYL696SaKVSm7VngpXlczHVEpz3kStWR5gfzriPBxXgMVcWmcbajRser7ARpCEfbxM1UJyv6oAYZWVSNErNzNVb4POqLYcCNySuC6xKhs9FrEQnyKjyk8wI4V"
             + "nrEMGrQ8e+qYSwYk9Gh6dKGoRMAPYVXQAO0fIsHF/T0a";
-
+#if !NET472
         private static string ExpectedSignature = "VocBRhpMmQ2XCzVehWSqheQLnU889gf3dhU4AnVnQTJjsKx/CM23qKDPkZDd2A/BnQsp99SN7ksIX5Raj0TPw"
             + "yN5OCN/YrNFNGoOFlTsGhgP/hyE8X3Duiq6sNO0SMvRYNPFFGlJFsp1Fw3Z94eYMg4/Wpw5s4+Jo5Zm/qY7aTJIqDKDQ3CNHLeJgcMUOc9sz01/GzoUYKDVODHSx"
             + "rYEk5ireFJFz9vP8P7Ha+VDUZuQIQdXer9NBbGFtYmWprY3nn4D3Dw93Sn0V0dIqYeIo91oKyslvMebmUM95S2PyIJdEpPb2DJDxjvX/0LLwSWlSXRWy9gapWoBk"
             + "b4ynqZBsg==";
+#endif
 
         [Fact]
         public void GetSignatureTest()