patch 9.0.1941: Memory leak detected

Problem:  Memory leak detected (after 9.0.1928)
Solution: Free arg_objm in get_lambda_tv()

closes: #13181

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yegappan Lakshmanan <yegappan@yahoo.com>
diff --git a/src/userfunc.c b/src/userfunc.c
index a27ff98..e0c1d5f 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -1721,7 +1721,10 @@
     eval_lavars_used = old_eval_lavars;
     vim_free(tofree2);
     if (types_optional)
+    {
 	ga_clear_strings(&argtypes);
+	ga_clear(&arg_objm);
+    }
 
     return OK;
 
@@ -1732,6 +1735,7 @@
     if (types_optional)
     {
 	ga_clear_strings(&argtypes);
+	ga_clear(&arg_objm);
 	if (fp != NULL)
 	    vim_free(fp->uf_arg_types);
     }