Format HTTPError.log_message only if args provided

[hXtreme]

Attempts to fix the jupyter_server/issues/1503 issue

For details please see the linked issue. TLDR is that if the log_message contents have the literal '%' those are getting converted to '%%' when no formatting args are specified. When HTTPError.__str__ is called, log_message is always %-formatted even when no formatting args are specified, and the '%' literal replacement is likely to avoid issues here.

This pr performs %-formatting of log_message only when required (args are specified) to avoid having to do the literal replacement.

While not completely a parallel example this is more or less what python's logging module does when creating a string out of a LogRecord:

https://github.com/python/cpython/blob/e06bebb87e1b33f7251196e1ddb566f528c3fc98/Lib/logging/__init__.py#L391-L402

If this is intentionally done for some special reason such as security then maybe this issue could be tackled solely on the jupyter side.

related to: #1393

cc: @ptch314

[hXtreme]

It would be great if someone could point me to instruction on how to run tests/lints on the code :)

[bdarnell]

I'm not sure we have this documented, but the simplest way is to install tox and run something like tox -e lint,docs,py313-full (For simple changes like this you can usually omit docs and -full, and feel free to change py313 to a different version if you have something else installed)

[hXtreme]

@bdarnell I've updated the pr to pass tox -e py312-full

some tests were skipped with the following output:

python -bb -m tornado.test
Ran 1209 tests in 15.091s

OK (skipped=3)
Some tests were skipped because: needs fix, no testable future
imports, py312 has its own check for test case returns

python -O -m tornado.test
Ran 1209 tests in 17.613s

OK (skipped=3)
Some tests were skipped because: needs fix, no testable future
imports, py312 has its own check for test case returns

python -m tornado.test --httpclient=tornado.curl_httpclient.CurlAsyncHTTPClient
Ran 1209 tests in 21.064s

OK (skipped=4)
Some tests were skipped because: curl client accepts invalid headers,
needs fix, no testable future imports, py312 has its own check for
test case returns

python -m tornado.test --resolver=tornado.platform.caresresolver.CaresResolver
Ran 1209 tests in 17.034s

OK (skipped=4)
Some tests were skipped because: localhost does not resolve to ipv4,
needs fix, no testable future imports, py312 has its own check for
test case returns

I couldn't run docs test