fix(sdk): returns the correct string associated with enums (#200)

Author: sujankota

sdk/src/main/java/io/opentdf/platform/sdk/AssertionConfig.java

@@ -34,6 +34,11 @@ public enum Scope {
         Scope(String scope) {
             this.scope = scope;
         }
+
+        @Override
+        public String toString() {
+            return scope;
+        }
     }
 
     public enum AssertionKeyAlg {
@@ -51,6 +56,11 @@ public enum AppliesToState {
         AppliesToState(String state) {
             this.state = state;
         }
+
+        @Override
+        public String toString() {
+            return state;
+        }
     }
 
     public enum BindingMethod {
@@ -61,6 +71,11 @@ public enum BindingMethod {
         BindingMethod(String method) {
             this.method = method;
         }
+
+        @Override
+        public String toString() {
+            return method;
+        }
     }
 
     static public class AssertionKey {