Introduce MissingRequiredFilesToDeleteException for Streaming Deletes

[shanielh]

Added a new exception, MissingRequiredFilesToDeleteException, to allow users
to inspect missing file details during streaming deletes.

• This exception extends ValidationException and preserves compatibility
  with the existing validation message.
• Users can now retrieve missing file locations via the getMissingLocations()
  method, instead of relying solely on the exception message.

[RussellSpitzer]

I think generally we wouldn't want to introduce new API concepts unless there is some usage of that API within the core library itself (Otherwise we are basically just opening up technical debt without tests or benefit). Do we have plans for introducing a usage in the repo somewhere?

At minimum I think we would want tests utilizing this API but I think a practical application would also be required as a justification.

[shanielh]

I think generally we wouldn't want to introduce new API concepts unless there is some usage of that API within the core library itself (Otherwise we are basically just opening up technical debt without tests or benefit). Do we have plans for introducing a usage in the repo somewhere?

At minimum I think we would want tests utilizing this API but I think a practical application would also be required as a justification.

I don't think there's a utilisation to the API in the core, my practical use is to check whether all files are already deleted or not in a Delete operation. This information already lies in the ValidationException, but it requires me to do string manipulation in order to get the information.

As a general rule of thumb, I suggest all information that lies in the exception message should be somehow accessible via API.