cleanup: remove CustomArrayErrorAttributes method from ASP.NET Core test controller

- Remove leftover CustomArrayErrorAttributes method that attempted to pass arrays to NoticeError()
- Error attributes do not support arrays and this functionality will not be implemented
- Ensures test applications only contain valid array attribute endpoints
- Maintains clean separation between AddCustomAttribute (supports arrays) and NoticeError (does not)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: tippmar-nr

tests/Agent/IntegrationTests/Applications/AspNetCoreWebApiCustomAttributesApplication/Controllers/AttributeTestingController.cs

@@ -96,17 +96,4 @@ public string CustomArrayWithNulls()
         return "success";
     }
 
-    [HttpGet]
-    [Route("api/CustomArrayErrorAttributes")]
-    public string CustomArrayErrorAttributes()
-    {
-        var errorAttributes = new Dictionary<string, object>
-        {
-            {"errorTags", new[] { "error", "critical", "timeout" }},
-            {"errorCodes", new[] { 500, 503, 404 }},
-        };
-        NewRelic.Api.Agent.NewRelic.NoticeError("Array error occurred.", errorAttributes);
-
-        return "success";
-    }
 }