The rp2 port was enabling SSL and had finalizers enabled via the "extra
features" level, but missed explicitly enabling `MICROPY_PY_SSL_FINALISER`
(like esp32, stm32, and mimxrt did).
This commit makes `MICROPY_PY_SSL_FINALISER` default to enabled if
finalizers are enabled, and removes the explicit setting of this for
esp32, stm32, mimxrt (because they all use the "extra features" level).
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>