fix(sensor-proxy): correctly skip selfheal regeneration during selfheal runs

The PULSE_SENSOR_PROXY_SELFHEAL env var is set to "1", but the check
was only looking for "true", causing selfheal to regenerate itself on
every run. This meant the cached installer would overwrite the selfheal
script with its (potentially older) version, defeating any fixes in
the selfheal script.

Now correctly checks for both "true" and "1".

Related to #849

scripts/install-sensor-proxy.sh

@@ -3427,7 +3427,7 @@ EOF"
     fi
 fi  # End of container-specific configuration
 
-if [[ "$SKIP_SELF_HEAL_SETUP" == "true" ]]; then
+if [[ "$SKIP_SELF_HEAL_SETUP" == "true" || "$SKIP_SELF_HEAL_SETUP" == "1" ]]; then
     print_info "Skipping self-heal safeguards during self-heal run"
 else
     # Install self-heal safeguards to keep proxy available