fix(json-cppagent-tests): wrap Assert.Throws sync lambdas with (Action) cast for NUnit 4 (CS0121)

Cascade rebase of chore/nunit-4-upgrade onto master post-TrakHound#221 surfaced
four fresh CS0121 ambiguity errors in JsonConditionsArrayShapeTests
(added by TrakHound#221) where bare `() =>` lambdas passed to Assert.Throws<T>
are ambiguous between the TestDelegate and Action overloads once NUnit
is upgraded to 4.x. TestDelegate is obsolete-as-error in NUnit 4, so
apply the same (Action) cast pattern established for the campaign in
ae03e24 (AgentUuidValidationTests) at the four new sites:

  Streams/JsonConditionsArrayShapeTests.cs L428, L498, L516, L530

Author: ottobolyos

tests/MTConnect.NET-JSON-cppagent-Tests/Streams/JsonConditionsArrayShapeTests.cs

@@ -425,8 +425,8 @@ public void Deserialize_legacy_v1_object_keyed_shape_throws_JsonException()
                 "\"Normal\":[{\"dataItemId\":\"n1\"}]," +
                 "\"Unavailable\":[{\"dataItemId\":\"u1\"}]}";
 
-            Assert.Throws<JsonException>(() =>
-                JsonSerializer.Deserialize<JsonConditions>(legacyV1));
+            Assert.Throws<JsonException>((Action)(() =>
+                JsonSerializer.Deserialize<JsonConditions>(legacyV1)));
         }
 
         /// <summary>
@@ -495,7 +495,7 @@ public void Deserialize_unknown_level_property_is_silently_ignored()
         [TestCase("false")]
         public void Deserialize_non_array_root_throws_JsonException(string wire)
         {
-            Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<JsonConditions>(wire));
+            Assert.Throws<JsonException>((Action)(() => JsonSerializer.Deserialize<JsonConditions>(wire)));
         }
 
         /// <summary>
@@ -513,7 +513,7 @@ public void Deserialize_non_array_root_throws_JsonException(string wire)
         [TestCase("[[]]")]
         public void Deserialize_scalar_or_array_element_throws_JsonException(string wire)
         {
-            Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<JsonConditions>(wire));
+            Assert.Throws<JsonException>((Action)(() => JsonSerializer.Deserialize<JsonConditions>(wire)));
         }
 
         /// <summary>
@@ -527,7 +527,7 @@ public void Deserialize_scalar_or_array_element_throws_JsonException(string wire
         [TestCase("not-json-at-all")]
         public void Deserialize_malformed_wire_throws_JsonException(string wire)
         {
-            Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<JsonConditions>(wire));
+            Assert.Throws<JsonException>((Action)(() => JsonSerializer.Deserialize<JsonConditions>(wire)));
         }
 
         /// <summary>