feat(local_visualizer.py): add check dir exist

[tpoisonooo]

Thanks for your contribution and we appreciate it a lot. The following instructions would make your pull request more healthy and more easily get feedback. If you do not understand some items, don't worry, just make the pull request and seek help from maintainers.

Motivation

add output dir check, output_file is actually an directory.

open-mmlab/mmdeploy#1039 needs it.

Modification

add os.mkdir

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[ZwwWayne]

Lint failed, can be merged after fix linting issue.

[tpoisonooo]

Lint failed, can be merged after fix linting issue.

done.