When a saga message does not contain SagaHistory, Improve the status bar error message

[indualagarsamy]

It is a valid scenario to have endpoints that contain saga information which does not load the SagaAudit plugin. When viewing these messages in ServiceInsight, the status bar reports an error.

[indualagarsamy]

@distantcam - I am having second thoughts on completely removing the status bar message for the following reasons:

• If the status bar doesn't contain any message then that might be misleading and user may not even look at the Logs tab.
• If we want the status message to not show, the error management is all done in one place, it feels yucky to add something that specifically checks the ResponseUri to see if it contains sagas in here: https://github.com/Particular/ServiceInsight/blob/master/src/ServiceInsight.Desktop/ServiceControl/DefaultServiceControl.cs#L384

However, it still makes sense to do a small improvement of changing the actual message we display in the status bar. Currently it says:
Operation Failed: Error executing the request: Data at the root level is invalid. Line1, position1., Status code is NotFound
I'd like to change it to the actual request, instead of the exception message.
So, it would be something like:
Operation Failed: Error executing the request: http://localhost:33333/api/sagas/<someguid>, Status code is NotFound

Proposed code change
Change Line 387 to

var errorMessage = response != null ? string.Format("Error executing the request: {0}, Status code is {1}", response.ResponseUri, response.StatusCode) : "No response was received.";

[johnsimons]

We are now not showing that error in the status bar, instead we load the tab but just display: