Export GOTRACEBACK=crash env variable (#18559)

### Why I did it

Improve visibility for telemetry crashes by allowing core to be dumped.

### How I did it

Export GOTRACEBACK=crash as an environment variable.

#### How to verify it

Manual test

1) Change telemetry binary to crash always, first line of telemetry.go main() -> panic("problem")
2) Add change to telemetry.sh
3) Restart telemetry
4) See core in /var/core

dockers/docker-sonic-telemetry/telemetry.sh

@@ -19,6 +19,7 @@ CERTS=$(echo $TELEMETRY_VARS | jq -r '.certs')
 
 TELEMETRY_ARGS=" -logtostderr"
 export CVL_SCHEMA_PATH=/usr/sbin/schema
+export GOTRACEBACK=crash
 
 if [ -n "$CERTS" ]; then
     SERVER_CRT=$(echo $CERTS | jq -r '.server_crt')