Use the proper parameter for SNMP timeout (#435)

The SNMP_TIMEOUT environment variable in the manifest_snmp_traps.j2
template for Service Telemetry Operator uses the wrong parameter,
passing port instead of timeout value to the template.

This change updates the template to use the appropriate parameter as
input.

Closes: rhbz#2213016

roles/servicetelemetry/templates/manifest_snmp_traps.j2

@@ -28,7 +28,7 @@ spec:
  - name: SNMP_PORT
  value: "{{ servicetelemetry_vars.alerting.alertmanager.receivers.snmp_traps.port }}"
  - name: SNMP_TIMEOUT
- value: "{{ servicetelemetry_vars.alerting.alertmanager.receivers.snmp_traps.port }}"
+ value: "{{ servicetelemetry_vars.alerting.alertmanager.receivers.snmp_traps.timeout }}"
  - name: ALERT_OID_LABEL
  value: "{{ servicetelemetry_vars.alerting.alertmanager.receivers.snmp_traps.alert_oid_label }}"
  - name: TRAP_OID_PREFIX