Fix dataframe.replace when columns contain pd.na
- [x] closes #47480
- [x] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
Thanks for the pull request but we already have a pull request open working on this issue: https://github.com/pandas-dev/pandas/pull/49805

Since the above PR doesn't appear stale yet, we'll let that user to continue to work on this issue so closing this PR for now. If you're interested in contributing, we recommend tackling issues labeled `good first issue` not assigned to any users  yet