fix(extensions): correct Options type

[marcalexiei]

Refine extensions rule Options:

• since the function used by the rule to get file extension is called is called getModifier I renamed all relevant information using modifier name.
• Refined Options with more explicit array types
• Changed buildProperties checks to avoid type checking errors

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🦋 Changeset detected

Latest commit: d78d9da

The changes in this PR will be included in the next version bump.

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Name	Type
eslint-plugin-import-x	Patch

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[SukkaW]

LGTM, thanks!