Add SIGTERM handler to TXE for graceful shutdown

[CreeptoGengar]

Description:

• Added SIGTERM handler in TXE service to exit with code 0
• Updated bootstrap.sh to use dump_fail for TXE execution
• Fixes TODO: "I'd like to use dump_fail here, but TXE needs to exit 0 on receiving a SIGTERM"

Fixed #12318

[charlielye]

Didn't work as expected. Required changes done here #12427