Ensured that failed ajaxSends have their invocation callbacks cleared.

- Involved having two parameters for our error callback binder.
- This code path wasn't run for a while due to never receiving the origData in the callback, therefore had to remove some legacy functionality.
- Also added a test to ensure that failed sends clear invocation callbacks.

#2694 

Differences between this and dev/release = This branch performs ajaxSends with a string therefore the origData in the error handler has to be parsed.