fix(agent): Don't send only major version to vm package

Guzzle 7+ was sending only the major version to the vm package
If only major version is available, it should not be sent.

agent/lib_guzzle6.c

@@ -352,14 +352,20 @@ NR_PHP_WRAPPER_START(nr_guzzle6_client_construct) {
   zval* this_var = nr_php_scope_get(NR_EXECUTE_ORIG_ARGS);
 
   char* version = nr_php_get_object_constant(this_var, "VERSION");
-  if (NULL == version) {
-    version = nr_php_get_object_constant(this_var, "MAJOR_VERSION");
-  }
 
   if (NRINI(vulnerability_management_package_detection_enabled)) {
     // Add php package to transaction
     nr_txn_add_php_package(NRPRG(txn), PHP_PACKAGE_NAME, version);
   }
+
+  /*
+ * If we were unable to get the full version before, at least we can extract
+ * the major version to send to the supportability metric.
+ * This is relevant to guzzle7+ which no longer supplies full version.
+ */
+  if (NULL == version) {
+    version = nr_php_get_object_constant(this_var, "MAJOR_VERSION");
+  }
   nr_fw_support_add_package_supportability_metric(NRPRG(txn), PHP_PACKAGE_NAME,
                                                   version);
   nr_free(version);