feat(useAxios): awaitable execute method

[FRSgit]

simplify execute var definitions
migrate to async methods to silent vitest warnings

resolves #1607

BREAKING CHANGE: change return type of useAxios.execute method to PromiseLike result

Signed-off-by: Jakub Freisler jakub@frsource.org

Description

This PR make execute method of the useAxios composable an awaitable one. In general - execute function returns an PromiseLike object containing then function that resolves with newest response data.

Additional context

Other things are that are important:

• vitest deprecated writing "callback-style tests" - so useAxios tests have been rewritten to return Promise,
• simplified a bit the way _url and config variables are declared within execute method.

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Contributing Guidelines.
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