Let \( z \) be a complex number such that \( \lvert z-6 \rvert = 5 \) and \( \lvert z + 2 - 6i \rvert = 5 \). Then the value of \( z^{3} + 3z^{2} - 15z + 141 \) is equal to:
\( 37 \)
\( 50 \)
\( 61 \)
\( 42 \)
