Terms/Tags are not getting created correctly when we select common taxonomy between enabled features.

[iamdharmesh]

Describe the bug

During working on e2e using cypress PR(#334), I noticed that when we select common taxonomy between enabled features, then terms/tags are not getting created correctly. Created terms/tags are not the combinations of the terms of the selected features instead it gets overwritten and ended up creating terms/tags of the only one feature. Please check screenshots for more information.

Based on the initial investigation this is happening because wp_set_object_terms overwrites terms/tags linked by other features
https://github.com/10up/classifai/blob/develop/includes/Classifai/Watson/Linker.php#L116.

Steps to Reproduce

1. Go to ClassifAI > Language Processing and setup API credentials
2. Enable All features (category, keywords, etc...) and assign related Watson taxonomy to each feature.
3. Create a post and note the terms created in each taxonomy.
4. Go to Language Processing settings and update "Tag" as a taxonomy for each feature.
5. Update a post created in step 3, check created tags. Created tags should be a combination of all terms created in step 3, but only a few tags are getting created.

Screenshots, screen recording, code snippet

Separate taxonomy for each features	Common taxonomy between features

Environment information

No response

WordPress information

No response

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