Update dependency sinon to v21

[balena-renovate]

This PR contains the following updates:

Package	Type	Update	Change
sinon (source)	devDependencies	major	^20.0.0 -> ^21.0.0

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Release Notes

sinonjs/sinon (sinon)

v21.0.0

Compare Source

• fd10f13f
  chore!: remove assert.failException property (#​2659) (Morgan Roderick)

  This was used for allowing customisation of the thrown error between
  sandboxes and for customisation for integrations (most likely from the
  days of BusterJS).

  To my knowledge and what I've been able to find on GitHub, this has
  never had any production use by end users.

  BREAKING CHANGE: this removes assert.failException from the API

Released by Morgan Roderick on 2025-06-13.

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