Fix TypeError thrown for certain OC list type results

[michaelnchin]

Issue #, if available: N/A

Description of changes:

• Implement additional checks to catch TypeError being thrown when attempting to create a visualization network from an invalid openCypher list-type results set.
• Fix some issues in openCypher integration tests

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[krlawrence]

Looks good. Is try catch all we can do for this case?

[michaelnchin]

The current OC network vertex/edge validity check assumes that any individual result passed in can only be of dict / list / other iterable type.

We now know non-iterable types results (e.g. int) may also be passed in as results, and that these cannot be valid network elements regardless.

So, having a broad try/catch clause to cover the rest of these possible invalid result types feels like the most straightforward way to deal with the issue.