drivers: intc: esp32: fix and reset flags when freeing interrupt

Fix bitwise operation when freeing an interrupt to correctly clear the
VECDESC_FL_NONSHARED, VECDESC_FL_RESERVED, and VECDESC_FL_SHARED flags.
Also reset the interrupt source to ETS_INTERNAL_UNUSED_INTR_SOURCE to
ensure proper cleanup and prevent issues with future allocations.

Signed-off-by: Sylvio Alves <sylvio.alves@espressif.com>