DOC: Not running clipboard examples in the doc
- [X] xref #26648, #26103
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

The clipboard example in the docs is failing when building in azure (#26648), and had to be previously fixed in travis (#26103). I don't think there is any need to run those examples, and we can keep things simpler. This adds the same value to the doc reader, and doesn't require to set up a clipboard service in the doc builds. Also, we're thinking on having a doc build for windows (#26574) not sure if that could cause new problems.

CC: @jorisvandenbossche 

