Use testing context when possible

[jsoriano]

Go 1.24.0 introduced a context in testing objects that is cancelled after the test is finished, but before registered cleanup functions are executed. See https://tip.golang.org/doc/go1.24#testingpkgtesting.

Apart from providing a non-nil context, this new context helps ensuring that resources that should be finished by context cancellation are actually finished.

In general there is no reason to don't use this context, the only reasons would be:

• Contexts in cleanup functions, as this context will be cancelled at this point.
• Contexts for resources that should persist along tests. Something I think we don't have in this project.

[elasticmachine]

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cc @jsoriano

[mrodm]

🚀