Function lookup_json_array

Try to look up a dotted identifier (e.g. `state.files`, `params.globs`, `matrix.batch`) as a raw JSON value and, if it is an array of strings, return the items. Returns `None` for non-array values or unknown paths.

(
    expression: &str,
    params: &HashMap<String, Value>,
    state: &HashMap<String, Value>,
    matrix_values: Option<&HashMap<String, Value>>,
)