cJSON: include only source file objects for cmake build

Test file can cause build issues in some cases, since it has its own main() function

components/json/CMakeLists.txt

@@ -1,4 +1,3 @@
 idf_component_register(SRCS "cJSON/cJSON.c"
                             "cJSON/cJSON_Utils.c"
-                            "cJSON/test.c" 
                     INCLUDE_DIRS cJSON)