fix(tests): propagate exist_ok in write_file_tree

Propagate the exist_ok parameter through recursive calls in
write_file_tree to prevent failures when directories already exist.

Signed-off-by: Aryan Chalotra <aryanchalotra96@gmail.com>

Author: aryanchalotraa

tests/common_utils/__init__.py

@@ -32,4 +32,4 @@ def write_file_tree(tree_def: dict, rooted_at: StrPath, exist_ok: bool = False)
             entry_path.write_text(value)
         else:
             entry_path.mkdir(exist_ok=exist_ok)
-            write_file_tree(value, entry_path)
+            write_file_tree(value, entry_path, exist_ok=exist_ok)