Update microbatch tests to handle update wherein incremental strategies are always validated

[QMalcolm]

Resolves N/A

Problem

A test broke because we fixed a bug in dbt-adapters (and the test depended on the bug 🙃)

Solution

Fix the test to work with the fixt dbt-adapters behavior

Checklist

• [X] I have read the contributing guide and understand what's expected of me.
• [X] I have run this code in development, and it appears to resolve the stated issue.
• [X] This PR includes tests, or tests are not required or relevant for this PR.
• [X] This PR has no interface changes (e.g., macros, CLI, logs, JSON artifacts, config files, adapter interface, etc.) or this PR has already received feedback and approval from Product or DX.
• [X] This PR includes type annotations for new and modified functions.