Change tests to dump the first migration and use for all other tests

[diversemix]

Description

• add default env vars for pg client
• add postgresql-client to the docker image
• Change tests to dump the first migration and use for all other tests

Please include:

• a summary of the changes
• links to any related issue/ticket
• any additional relevant motivation and context
• details of any dependency updates that are required for this change

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Type of change

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• Bug fix
• New feature
• Breaking change
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• Documentation update
• Remove legacy code
• Dependency update

How Has This Been Tested?

Please describe the tests that you added to verify your changes.

Reviewer Checklist

• DB_CLIENT DEPENDENCY IS ON THE LATEST VERSION
• The PR represents a single feature (small drive-by fixes are also ok)
• The PR includes tests that are sufficient for the level of risk
• The code is sufficiently commented, particularly in hard-to-understand areas
• Any required documentation updates have been made
• Any TODOs added are captured in future tickets
• No FIXMEs remain

[katybaulch]

All of the cookies, Thankyou so much!!!🍪⭐

[katybaulch]

Amazing!!!!!