Make eval test resilient to error format (#1278)

Author: kblok

lib/PuppeteerSharp.Tests/PageTests/EvaluateTests.cs

@@ -125,10 +125,10 @@ public async Task ShouldRejectPromiseWithExeption()
         {
             var exception = await Assert.ThrowsAsync<EvaluationFailedException>(() =>
             {
-                return Page.EvaluateFunctionAsync("() => not.existing.object.property");
+                return Page.EvaluateFunctionAsync("() => not_existing_object.property");
             });
 
-            Assert.Contains("not is not defined", exception.Message);
+            Assert.Contains("not_existing_object", exception.Message);
         }
 
         [Fact]