Add assertions to mnemonic generation

[insumisos]

Description

Problem or Issue being addressed

The dice and coin seed generation functions are trusting that the UI will submit the appropriate number of dice rolls or coin flips. Should the UI not do this, for whatever reason, then insufficient entropy could be passed to the hash function.

Solution

Don't trust the UI (client side validation), do local validation and fail hard if there isn't sufficient entropy.

Additional Information

Since the asserts are not handled then will probably crash the UI but that's probably desirable.

This pull request is categorized as a:

• New feature
• Bug fix
• Code refactor
• Documentation
• Other

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Checklist

I ran pytest locally

• All tests passed before submitting the PR
• I couldn't run the tests
• N/A

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I added or updated tests

Any new or altered functionality should be covered in a unit test. Any new or updated sequences require FlowTests.

• Yes
• No, I’m a fool
• N/A

Removed ColdCard test as their example has small number of rolls (since it was supposed to be mixed with a HRNG) which fails. Instead tests whether assertion is thrown for invalid rolls.

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I tested this PR hands-on on the following platform(s):

• Raspberry Pi OS Manual Build
• SeedSigner OS on a Pi0/Pi0W board
• Emulator

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I have reviewed these notes:

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• I understand