Remove redundant show-verbose-logs empty-string guard

[shaanmajid]

The action.yaml defaults "true" for show-verbose-logs, so the Actions runtime always provides a value; it is impossible forshowVerboseLogsInput to be an empty string. The === '' ? true : guard was dead code; getBooleanInput alone is sufficient.

Test mock defaults updated to reflect the runtime behavior (since action.yaml defaults are resolved before getInput is called).