Fix: Use only one blank line to separate sections or paragraphs
By running `./scripts/validate_docstrings.py --errors=GL03 --format=azure`, I was able to get the list of GL03 errors with files and line numbers where these errors occurred.

I fixed a big portion of these issues so far.

@datapythonista 

- [ ] closes #23870 
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

