fix(ingestion): looker - Handling gracefully invalid json in query dynamic field

[treff7es]

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

[github-actions]

Unit Test Results (build & test)

334 tests  ±0   334 ✔️ ±0   3m 2s ⏱️ ±0s
  78 suites ±0       0 💤 ±0 
  78 files   ±0       0 ❌ ±0 

Results for commit 4165c14. ± Comparison against base commit 4da3d13.

[github-actions]

Unit Test Results (metadata ingestion)

       5 files         5 suites   1h 28m 41s ⏱️
   551 tests    547 ✔️     3 💤 1 ❌
2 470 runs  2 364 ✔️ 105 💤 1 ❌

For more details on these failures, see this check.

Results for commit 4165c14.

[shirshanka]

LGTM. Test failures seem unrelated.