linter: Fix checking for inline refs.

The current linter disallowed the pattern
where multiple refs were present without
an additional parameter in allOf, which should
be valid.

Fixed the condition to allow the change.

tools/check-openapi

@@ -13,7 +13,7 @@ function checkRefSiblings(file, path, data) {
     if (typeof data === "object" && data !== null) {
         if (
             "allOf" in data &&
-            Object.values(data.allOf).filter((subschema) => !("$ref" in subschema)).length !== 1
+            Object.values(data.allOf).filter((subschema) => !("$ref" in subschema)).length > 1
         ) {
             console.error(
                 `${file}: Too many inline allOf subschemas at ${JSON.stringify(