test(bigframes): Fix nb test project id injection for 4 examples

[TrevorBergeron]

Thank you for opening a Pull Request! Before submitting your PR, there are a few things you can do to make sure it goes smoothly:

• Make sure to open an issue as a bug/issue before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
• Ensure the tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

Fixes #<issue_number_goes_here> 🦕

[gemini-code-assist]

Code Review

This pull request standardizes the project ID variable name to PROJECT_ID and adds @param tags for parameterization across several notebooks. Feedback was provided regarding a formatting inconsistency in the @param tag within the remote_function_vertex_claude_model.ipynb notebook to maintain consistency with other files.