[FSTORE-1247] Raise DataValidationError on validation failure if ingestion set to strict

[vatj]

…a dataframe if the validation ingestion policy is set to strict (#1226)

• Add DataValidationException class

• Raise DataValidationException on validation failure if validation ignestion policy set to strict

• Fix associated unit test

• Append to insert documentation

• Raise exception also when inserting only in the online Feature Store for External FG

• Add documentation to insert for External FG

• Refactor get_feature_group_url and improve DataValidationException message

• Remove pytest bigquery.json

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This PR adds/fixes/changes...

• please summarize your changes to the code
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How Has This Been Tested?

• Unit Tests
• Integration Tests
• Manual Tests on VM

Checklist For The Assigned Reviewer:

- [ ] Checked if merge conflicts with master exist
- [ ] Checked if stylechecks for Java and Python pass
- [ ] Checked if all docstrings were added and/or updated appropriately
- [ ] Ran spellcheck on docstring
- [ ] Checked if guides & concepts need to be updated
- [ ] Checked if naming conventions for parameters and variables were followed
- [ ] Checked if private methods are properly declared and used
- [ ] Checked if hard-to-understand areas of code are commented
- [ ] Checked if tests are effective
- [ ] Built and deployed changes on dev VM and tested manually
- [x] (Checked if all type annotations were added and/or updated appropriately)