fix wrong error message (#3411)

fixes #3410

Author: ErikEJ

src/Microsoft.Data.SqlClient/src/Microsoft/Data/Common/ConnectionString/PoolBlockingUtilities.cs

@@ -128,7 +128,7 @@ internal static PoolBlockingPeriod ConvertToPoolBlockingPeriod(string keyword, o
                 }
                 else
                 {
-                    throw ADP.InvalidEnumerationValue(typeof(ApplicationIntent), (int)eValue);
+                    throw ADP.InvalidEnumerationValue(typeof(PoolBlockingPeriod), (int)eValue);
                 }
             }
         }