This PR changes `from pydantic import BaseModel` to `from
synapse._pydantic_compat import BaseModel` (as well as `constr`,
`conbytes`, `conint`, `confloat`).

It allows `check_pydantic_models.py` to mock those pydantic objects only
in the synapse module, and not interfere with pydantic objects in
external dependencies.

This should solve the CI problems for #17144, which breaks because
`check_pydantic_models.py` patches pydantic models from
[scim2-models](https://scim2-models.readthedocs.io/).

/cc @DMRobertson @gotmax23
fixes #17659 


### Pull Request Checklist

<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->

* [x] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
  - Use markdown where necessary, mostly for `code blocks`.
  - End with either a period (.) or an exclamation mark (!).
  - Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [x] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct
(run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))

I thought ruff check would also format, but it doesn't.

This runs ruff format in CI and dev scripts. The first commit is just a
run of `ruff format .` in the root directory.

During the migration the automated script to update the copyright
headers accidentally got rid of some of the existing copyright lines.
Reinstate them.

While maintaining support with pydantic v1.

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

This reverts commit 6d543d6d.

* Update mypy and mypy-zope

* Unignore assigning to LogRecord attributes

Presumably https://github.com/python/typeshed/pull/8064 makes this ok

Cherry-picked from #13521

* Remove unused ignores due to mypy ParamSpec fixes

https://github.com/python/mypy/pull/12668

Cherry-picked from #13521

* Remove additional unused ignores

* Fix new mypy complaints related to `assertGreater`

Presumably due to https://github.com/python/typeshed/pull/8077



* Changelog

* Reword changelog

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>