[FE-5985] Error when configuring start_ts and cursor at the same time

[ptpaterson]

FE-5985

Description

Added additional input validation for StreamIterator and ChangeFeedIterator constructors: raise an error if both cursor and start_ts are provided as options.

Motivation and context

We currently allow both start_ts and cursor options to be provided at the same time for Streams and ChangeFeeds. When that happens, cursor is used and start_ts is silently ignored. We should raise an error instead.

This is a follow up to a previous discussion: #192 (comment)

How was the change tested?

Additional integration tests were added to confirm an error is raised.

Screenshots (if appropriate):

Change types

• • Bug fix (non-breaking change that fixes an issue)
• • New feature (non-breaking change that adds functionality)
• • Breaking change (backwards-incompatible fix or feature)
    • The cursor option is part of the beta release of change feeds, so while technically breaking, it only breaks the experimental/beta features that have been released.

Checklist:

• • My code follows the code style of this project.
• • My change requires a change to Fauna documentation.
• • My change requires a change to the README, and I have updated it accordingly.

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[erickpintor]

LGTM