fix: Resolve error when cloning Python models (#645)

[jeancochrane]

Description

Currently, it is not possible to clone Python models using dbt clone because of an outdated reference in the create_or_replace_view macro to a sql context variable that returns None for Python models. This PR represents a one-line change to update that reference to the newer compiled_code context variable that implements the exact same logic as sql but supports Python models as well.

Closes #645.

Models used to test - Optional

Tests have been added to the tests/functional/adapter/test_python_submissions.py file under a new class TestPythonClonePossible. The models defined by this test were used for testing. It didn't seem like unit testing was appropriate in this case, so I focused exclusively on functional testing instead.

Checklist

• You followed contributing section
• You kept your Pull Request small and focused on a single feature or bug fix.
• You added unit testing when necessary
• You added functional testing when necessary

[jeancochrane]

@jessedobbelaere @Jrmyy @mattiamatrix @nicor88 @svdimchenko Anything else you need fro me ahead of review? I'm happy to wait if you're crunched for review time right now, just want to make sure this doesn't fall through the cracks!

[nicor88]

@Avinash-1394 do you mind to have a look as well?

[nicor88]

Thanks for the fix @jeancochrane