[Classification] Ensure that the classification feature suggests or sets terms for enabled taxonomies only.

[iamdharmesh]

Description of the Change

While testing PR #804, I noticed that the plugin suggests (for manual mode) or sets (for automatic classification mode) terms for posts on all taxonomies for OpenAI Embeddings and Azure OpenAI Embeddings providers, terms should be suggested/set only for enabled taxonomies.

This PR fixes this issue by suggesting or setting terms for enabled taxonomies only.

How to Test the Change

1. Checkout to the trunk branch.
2. Set the classification feature using OpenAI Embeddings or Azure OpenAI Embeddings.
3. Disable Classification for the Post Tag Taxonomy.
4. Create a post, add some content, and click on the "Suggest terms & tags" button (for Manual mode) or save the post (for Automatic mode).
5. Notice that terms are suggested or set for all taxonomies (categories and tags) even if tags are disabled.
6. Checkout to this PR branch.
7. Create a post, add some content, and click on the "Suggest terms & tags" button (for Manual mode) or save the post (for Automatic mode).
8. Notice that terms are suggested or set for only the enabled taxonomies.

Changelog Entry

Fixed - Ensure that the classification feature suggests or sets terms for enabled taxonomies only.

Credits

Props @iamdharmesh

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.