Fix smoke test JSON parsing

pikit-smoke-test.sh

@@ -84,10 +84,7 @@ extract_json_line() {
 json_get() {
   local key="$1"
   if command -v python3 >/dev/null 2>&1; then
-    python3 - "$key" <<'PY'
-import json
-import sys
-
+    python3 -c 'import json,sys
 key=sys.argv[1]
 try:
     data=json.load(sys.stdin)
@@ -99,7 +96,7 @@ if isinstance(val, bool):
     print("true" if val else "false")
 else:
     print(val)
-PY
+' "$key"
   elif command -v jq >/dev/null 2>&1; then
     jq -r --arg key "$key" '.[$key] // empty'
   else
@@ -144,8 +141,7 @@ check_api() {
     return
   fi
   if command -v python3 >/dev/null 2>&1; then
-    if printf "%s" "$body" | python3 - <<'PY'
-import json, sys
+    if printf "%s" "$body" | python3 -c 'import json,sys
 try:
     data=json.load(sys.stdin)
 except Exception:
@@ -154,7 +150,7 @@ for key in ("services", "hostname", "uptime_seconds"):
     if key in data:
         sys.exit(0)
 sys.exit(1)
-PY
+'
     then
       status OK "API responds with JSON"
     else