* boards: cuav/x25-super: add multi-instance heater support
Restore heater support removed in #26621 using the generic
multi-instance heater driver from #26325. Defines HEATER_NUM 2
for the two IMU heater outputs (PB10, PE6).
* boards: cuav/x25-super: fix heater IMU IDs and temp from hw test
Update defaults per @cuav-chen2 hardware testing:
- HEATER1_IMU_ID: 2818066 (SCH16T)
- HEATER2_IMU_ID: 3014698 (IIM42653)
- HEATER2_TEMP: 65°C
* Update boards/cuav/x25-super/init/rc.board_defaults