dynamic_modules: adds integration tests

[mathetake]

Commit Message: dynamic_modules: adds integration tests
Additional Description:

This adds various integration test cases for dynamic modules
that cover all currently implemented callbacks. While running
tests, I discovered a few edge cases around decodeData and
encodeData, so I fixed it.

Risk Level: low
Testing: added
Docs Changes: n/a
Release Notes: n/a
Platform Specific Features: n/a

[repokitteh-read-only]

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Please mark your PR as ready when you want it to be reviewed!

🐱

Caused by: #38285 was opened by mathetake.

see: more, trace.

[mathetake]

/assign @mattklein123