feature(ingestion/lookml): Report view file missing/parsing errors as warnings

[skrydal]

Checklist

• The PR conforms to DataHub's Contributing Guideline (particularly Commit Message Format)
• Links to related issues (if applicable)
• Tests for the changes have been added/updated (if applicable)
• Docs related to the changes have been added/updated (if applicable). If a new feature has been added a Usage Guide has been added for the same.
• For any breaking change/potential downtime/deprecation/big changes an entry has been made in Updating DataHub

[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ahub/ingestion/source/looker/looker_file_loader.py	0.00%	2 Missing ⚠️

Files with missing lines	Coverage Δ
...c/datahub/ingestion/source/looker/looker_config.py	96.52% <100.00%> (ø)
...ahub/ingestion/source/looker/looker_file_loader.py	80.00% <0.00%> (ø)

... and 1 file with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b75d3ed...bbbb35c. Read the comment docs.