Handle side-loading node data from separate APIs

[bjester]

Summary

Description of the change(s) you made

• Updates the Import search to side-load nodes from either the normal API endpoint or the public API which is cached
• Removes some returned fields from search API, since it's returning only a subset of what is needed
• Adds Kolibri public API frontend utilities
• Fixes inconsistent issue with DropdownWrapper.vue handling string values for numeric prop

Manual verification steps performed

1. Create a public channel, Channel A
2. Add some content to Channel A, with all the extras like thumbnail and metadata
3. Publish the channel
4. Sign out and back in
5. Do NOT open Channel A
6. Create a new channel, Channel B
7. Add new content to Channel B by using Import search
8. Verify the core details are represented by the search card, preview, and you're able to complete the import

Screenshots (if applicable)

Does this introduce any tech-debt items?

---

Reviewer guidance

How can a reviewer test these changes?

• Does this work for public channel searches?
• Does this work for searching your own channels?

Are there any risky areas that deserve extra testing?

References

Resolves: #4104
Resolves: #4102
Partially addresses: #4101

Comments

---

Contributor's Checklist

PR process:

• If this is an important user-facing change, PR or related issue the CHANGELOG label been added to this PR. Note: items with this label will be added to the CHANGELOG at a later time
• If this includes an internal dependency change, a link to the diff is provided
• The docs label has been added if this introduces a change that needs to be updated in the user docs?
• If any Python requirements have changed, the updated requirements.txt files also included in this PR
• Opportunities for using Google Analytics here are noted
• Migrations are safe for a large db

Studio-specifc:

• All user-facing strings are translated properly
• The notranslate class been added to elements that shouldn't be translated by Google Chrome's automatic translation feature (e.g. icons, user-generated text)
• All UI components are LTR and RTL compliant
• Views are organized into pages, components, and layouts directories as described in the docs
• Users' storage used is recalculated properly on any changes to main tree files
• If there new ways this uses user data that needs to be factored into our Privacy Policy, it has been noted.

Testing:

• Code is clean and well-commented
• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Any new interactions have been added to the QA Sheet
• Critical and brittle code paths are covered by unit tests

---

Reviewer's Checklist

This section is for reviewers to fill out.

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[vkWeb]

@bjester sir, I am not sure what's the reason, but I see import from other channel search is not working on https://hotfixes.studio.learningequality.org/. The API do return a response in reasonable time:-