fix(ingestion): enforce correct behaviour for commit policy

[claudio-benfatto]

fixes a bug in the CommitPolicy enum that was causing an incorrect behaviour during the pipeline process_commits stage.

class CommitPolicy(Enum):
    ALWAYS = auto
    ON_NO_ERRORS = auto
    ON_NO_ERRORS_AND_NO_WARNINGS = auto

meant that ALWAYS == ON_NO_ERRORS == ON_NO_ERRORS_AND_NO_WARNINGS that would cause an incorrect
behaviour when calling the process_commits() method in the pipeline

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)

[github-actions]

Unit Test Results (build & test)

  68 files  ±0    68 suites  ±0   11m 58s ⏱️ - 2m 37s
596 tests ±0  537 ✔️ ±0  59 💤 ±0  0 ❌ ±0 

Results for commit c512448. ± Comparison against base commit 306fe0b.

[github-actions]

Unit Test Results (metadata ingestion)

    3 files      3 suites   39m 29s ⏱️
313 tests 313 ✔️   0 💤 0 ❌
899 runs  872 ✔️ 27 💤 0 ❌

Results for commit c512448.

[shirshanka]

great catch. thanks!