Better user agent string and descriptions

[yungshinlintw]

• Refactored client initialization in classifier.ipynb, content_extraction.ipynb, field_extraction.ipynb, management.ipynb, and analyzer_training.ipynb to include a user agent for tracking sample usage.
• Updated documentation in classifier.ipynb to clarify the integration of classification capabilities within the analyzer operation.

Purpose

• ...

Does this introduce a breaking change?

[ ] Yes
[x] No

Pull Request Type

What kind of change does this Pull Request introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[x] Documentation content changes
[ ] Other... Please describe:

How to Test

• Get the code

git clone [repo-address]
cd [repo-name]
git checkout [branch-name]
npm install

• Test the code

What to Check

Verify that the following are valid

• ...

Other Information