[sc-29773] Handle tables without columns

[usefulalgorithm]

🤔 Why?

Our crawler did not take into account for the case when row["columns"] is a None.

🤓 What?

• Fix NoneType not iterable error
• Refactor to make testing easier
• Added tests

🧪 Tested?

• Added unit test.
• Tested against stage environment.

☑️ Checks

• My PR contains actual code changes, and I have updated the version number in pyproject.toml.

[github-actions]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
13429	12020	90%	85%	🟢

New Files

No new covered files...

Modified Files

File	Coverage	Status
metaphor/unity_catalog/models.py	100%	🟢
metaphor/unity_catalog/queries.py	97%	🟢
TOTAL	99%	🟢

updated for commit: b7d06f5 by action🐍

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.50%. Comparing base (6d6cf69) to head (b7d06f5).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1040   +/-   ##
=======================================
  Coverage   89.50%   89.50%           
=======================================
  Files         211      211           
  Lines       13422    13429    +7     
=======================================
+ Hits        12013    12020    +7     
  Misses       1409     1409           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[elic-eon]

LGTM