BUG: Fix dtype inconsistency when appending to empty DataFrame
- [ ] closes #22621
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

*edit*: currently rewriting the DataFrame.append function
Hello @araraonline! Thanks for submitting the PR.

 - There are no PEP8 issues in the file [`pandas/core/frame.py`](https://github.com/araraonline/pandas/blob/9c87db1e82a559692c991c402cccc8e10cf33894/pandas/core/frame.py) !

 - There are no PEP8 issues in the file [`pandas/tests/frame/test_combine_concat.py`](https://github.com/araraonline/pandas/blob/9c87db1e82a559692c991c402cccc8e10cf33894/pandas/tests/frame/test_combine_concat.py) !

 This is not passing some tests that I did't notice before.

Gotta see what's wrong Got a question.

The problem ended up having a scope slightly bigger than what was mentioned in the Issue #22621

Now I'm working on a branch that fixes the dtype inconsistency when appending an array to a dframe, whether this dframe is empty or not.

Should I create a new PR? @araraonline no you can just update this one I'm currently working on rewriting the DataFrame.append function. When it is ready, the issue related here will be resolved