Bluetooth: Mesh: Fix transport tx and rx
Bluetooth: Mesh: Fix transport tx and rx

Fix seg_tx occupy when no segment not send
and allocate rx_seg when receive such message.

Fixes: #24101

Signed-off-by: Lingao Meng <8f6064192f8620c0146f45d3572dde5f622ecf12@gmail.com>

nashif/zephyr,finikorg/zephyr,nashif/zephyr,galak/zephyr,Vudentz/zephyr,finikorg/zephyr,galak/zephyr,nashif/zephyr,Vudentz/zephyr,Vudentz/zephyr,finikorg/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,finikorg/zephyr,galak/zephyr,Vudentz/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr