[pylint] Also report when the object isn't a literal (PLE1310)

[InSyncWithFoo]

Summary

Follow-up to #15984.

Previously, PLE1310 would only report when the object is a literal:

'a'.strip('//')  # error

foo = ''
foo.strip('//')  # no error

After this change, objects whose type can be inferred to be either str or bytes will also be reported in preview.

Test Plan

cargo nextest run and cargo insta test.

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

[MichaReiser]

Thank you. I'll convert this to draft until #15984 is merged. It's otherwise fairly hard to review the changes and I can't change the base because you're an external contributor :(