`Controller` cleanup: lazy imports no longer required

[kdmukai]

Description

At an earlier phase of the test suite refactor (a few months back) and before all the mocking had been put in to wall off the hardware-dependent libraries, the Controller was updated to use lazy imports (not explicitly importing via standard from blah import foo).

But with the test suite in its current form, this workaround is no longer necessary.

This pull request is categorized as a:

• [x] Code refactor

Checklist

• [x] I’ve run pytest and made sure all unit tests pass before sumbitting the PR

If you modified or added functionality/workflow, did you add new unit tests?

• [x] N/A

I have tested this PR on the following platforms/os:

• [x] Raspberry Pi OS Manual Build
• [ ] SeedSigner OS on a Pi0/Pi0W board

Note: Keep your changes limited in scope; if you uncover other issues or improvements along the way, ideally submit those as a separate PR. The more complicated the PR the harder to review, test, and merge.

[jdlcdl]

ACK tested

• no problems passing test suite and screenshot generator on linux desktop and raspi-os on pi2
• no problems doing a few random operations in seedsigner for raspi-os on pi2 and ss-os on pi0 w/ reproducible image 14a4ad3de2a661cf37631651f12cc3dcd96925297a338743e9b9816421f3a58b

[newtonick]

ACK, LGTM. Tested without any issues.