refactor: simplify application/octet-stream check

Author: Djaler

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinClientCodegen.java

@@ -962,7 +962,8 @@ public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<Mo
                         ).trim();
                         return "multipart/form-data".equals(mediaType)
                                 || "application/x-www-form-urlencoded".equals(mediaType)
-                                || (mediaType.startsWith("application/") && (mediaType.endsWith("json") || mediaType.endsWith("octet-stream")));
+                                || (mediaType.startsWith("application/") && mediaType.endsWith("json"))
+                                || "application/octet-stream".equals(mediaType);
                     };
                     operation.consumes = operation.consumes == null ? null : operation.consumes.stream()
                             .filter(isSerializable)