samples: bluetooth: fix adv_update error in bthome_sensor_template

- "bt_le_adv_update_data()" func calls just after bt_enable() call
 without completion of bt_ready() which is called as part of worker
 thread within init_work() causes issue where bluetooth controller
 has not been initialized and provides cb to app before app requests
 advertise_update to the stack.
- remove bt_ready() func and place content within main() post
 bt_enable() fixes this issue.

Signed-off-by: Nirav Agrawal <nirav.agrawal@nxp.com>