Fix unsuitable default value to bundle_root in ckpt_export (#7124)

Fixes #7123

### Types of changes
<!--- Put an `x` in all the boxes that apply, and remove the not
applicable items -->
- [x] Non-breaking change (fix or new feature that would not break
existing functionality).
- [ ] Breaking change (fix or new feature that would cause existing
functionality to change).
- [ ] New tests added to cover the changes.
- [ ] Integration tests passed locally by running `./runtests.sh -f -u
--net --coverage`.
- [ ] Quick tests passed locally by running `./runtests.sh --quick
--unittests --disttests`.
- [ ] In-line docstrings updated.
- [ ] Documentation updated, tested `make html` command in the `docs/`
folder.

---------

Signed-off-by: KumoLiu <[email protected]>

Author: KumoLiu

Diff for: monai/bundle/scripts.py

@@ -1273,7 +1273,6 @@ def ckpt_export(
         config_file_,
         filepath_,
         ckpt_file_,
-        bundle_root_,
         net_id_,
         meta_file_,
         key_in_ckpt_,
@@ -1285,26 +1284,30 @@ def ckpt_export(
         "config_file",
         filepath=None,
         ckpt_file=None,
-        bundle_root=os.getcwd(),
         net_id=None,
         meta_file=None,
         key_in_ckpt="",
         use_trace=False,
         input_shape=None,
         converter_kwargs={},
     )
+    bundle_root = _args.get("bundle_root", os.getcwd())
 
     parser = ConfigParser()
-
     parser.read_config(f=config_file_)
-    meta_file_ = os.path.join(bundle_root_, "configs", "metadata.json") if meta_file_ is None else meta_file_
-    filepath_ = os.path.join(bundle_root_, "models", "model.ts") if filepath_ is None else filepath_
-    ckpt_file_ = os.path.join(bundle_root_, "models", "model.pt") if ckpt_file_ is None else ckpt_file_
-    if not os.path.exists(ckpt_file_):
-        raise FileNotFoundError(f'Checkpoint file "{ckpt_file_}" not found, please specify it in argument "ckpt_file".')
+    meta_file_ = os.path.join(bundle_root, "configs", "metadata.json") if meta_file_ is None else meta_file_
     if os.path.exists(meta_file_):
         parser.read_meta(f=meta_file_)
 
+    # the rest key-values in the _args are to override config content
+    for k, v in _args.items():
+        parser[k] = v
+
+    filepath_ = os.path.join(bundle_root, "models", "model.ts") if filepath_ is None else filepath_
+    ckpt_file_ = os.path.join(bundle_root, "models", "model.pt") if ckpt_file_ is None else ckpt_file_
+    if not os.path.exists(ckpt_file_):
+        raise FileNotFoundError(f'Checkpoint file "{ckpt_file_}" not found, please specify it in argument "ckpt_file".')
+
     net_id_ = "network_def" if net_id_ is None else net_id_
     try:
         parser.get_parsed_content(net_id_)
@@ -1313,10 +1316,6 @@ def ckpt_export(
             f'Network definition "{net_id_}" cannot be found in "{config_file_}", specify name with argument "net_id".'
         ) from e
 
-    # the rest key-values in the _args are to override config content
-    for k, v in _args.items():
-        parser[k] = v
-
     # When export through torch.jit.trace without providing input_shape, will try to parse one from the parser.
     if (not input_shape_) and use_trace:
         input_shape_ = _get_fake_input_shape(parser=parser)