Use core.getBooleanInput() to retrieve boolean input values

[Yang-33]

This PR switches from evaluating values passed to skip-token-revoke as true if they are truthy in JavaScript, to using getBooleanInput. This change ensures that only proper YAML boolean values are recognized, preventing unintended evaluations to true.

• The definition of getBooleanInput is here: definition of core#getBooealnInput is here: https://github.com/actions/toolkit/blob/930c89072712a3aac52d74b23338f00bb0cfcb24/packages/core/src/core.ts#L188-L208

The documentation states, "If truthy, the token will not be revoked when the current job is complete", so this change could be considered a breaking change. This means that if there are users who rely on truthy and expect values like whitespace or "false" to be evaluated as true (though this is likely rare), it would be a breaking change.

• Boolean(" ") and Boolean("false") are both evaluated as true.

Alternatively, it can simply be considered a fix. How to handle this is up to the maintainer.

Resolve #216

[Yang-33]

@parkerbxyz PTAL~