Housekeeping: Move DB drivers to test scope

[JimTharioAmazon]

🔧 Type of changes

• new bid adapter
• bid adapter update
• new feature
• new analytics adapter
• new module
• module update
• bugfix
• documentation
• configuration
• dependency update
• tech debt (test coverage, refactorings, etc.)

✨ What's the context?

mysql-connector-j and postgresql drivers moved to test scope since they're not used in core.

🧠 Rationale behind the change

Investigation into CVE-2025-30706 for mysql-connector-j showed both drivers are used in test and can be removed from the release build.

🔎 New Bid Adapter Checklist

• verify email contact works
• NO fully dynamic hostnames
• geographic host parameters are NOT required
• direct use of HTTP is prohibited - implement an existing Bidder interface that will do all the job
• if the ORTB is just forwarded to the endpoint, use the generic adapter - define the new adapter as the alias of the generic adapter
• cover an adapter configuration with an integration test

🧪 Test plan

Local build, unit and functional tests complete successfully.

🏎 Quality check

• [Y] Are your changes following our code style guidelines?
• [N] Are there any breaking changes in your code?
• [Y] Does your test coverage exceed 90%?
• [N] Are there any erroneous console logs, debuggers or leftover code in your changes?