fix: pin pydantic to < 2.10 and restore cwd when building bento

[frostming]

Signed-off-by: Frost Ming [email protected]

What does this PR address?

Fixes #(issue)

Before submitting:

• Does the Pull Request follow Conventional Commits specification naming? Here are GitHub's
  guide on how to create a pull request.
• Does the code follow BentoML's code style, pre-commit run -a script has passed (instructions)?
• Did you read through contribution guidelines and follow development guidelines?
• Did your changes require updates to the documentation? Have you updated
  those accordingly? Here are documentation guidelines and tips on writting docs.
• Did you write tests to cover your changes?

[aarnphm]

what was the issue for this?

[frostming]

what was the issue for this?

When we build bento in Python code, it should better restore the cwd or it may cause problems, especially when the build ctx is a temp dir and gets destroyed after done.