Fix bug where bigquery extracts fail due to missing import

[kenxu95]

Describe your changes and why you are making these changes

Description here: https://linear.app/aqueducthq/issue/ENG-3026/aqueduct-install-bigquery-is-not-sufficient-for-bigquery-extracts-to

What the PR does:

• Better (or at least more consistent) error message if it doesn't exist:

- Also adds `db-dtypes` to the `aqueduct install bigquery` command.

Related issue number (if any)

ENG-3026

Loom demo (if any)

Checklist before requesting a review

• I have created a descriptive PR title. The PR title should complete the sentence "This PR...".
• I have performed a self-review of my code.
• I have included a small demo of the changes. For the UI, this would be a screenshot or a Loom video.
• If this is a new feature, I have added unit tests and integration tests.
• I have run the integration tests locally and they are passing.
• I have run the linter script locally (See python3 scripts/run_linters.py -h for usage).
• All features on the UI continue to work correctly.
• Added one of the following CI labels:
  • run_integration_test: Runs integration tests
  • skip_integration_test: Skips integration tests (Should be used when changes are ONLY documentation/UI)