Blocks: only use strings in block descriptions

[jeherve]

Note
I'm opening this PR as a suggestion to remove notices. We do not have to merge this if we are comfortable keeping notices in the browser console (thus increasing noise for developers) to ensure a better user experience for site owners.

Proposed changes:

Discussion: #26792

Until we have a better way to have custom descriptions for blocks, let's keep only strings to avoid notices. This isn't ideal since we're using useful information like links to support documentation, but at least we're getting rid of notices.

Closes #29402

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

• Non-plain-text block description is being deprecated in WordPress 6.2 #26792
• WordPress 6.2 compat' primary issue: WordPress 6.2 compatibility #27795

Does this pull request change what data or activity we track or use?

• No

Testing instructions:

On a site that runs WordPress 6.2 RC, go to Posts > Add New and open the browser console. You should not see any notices like this one:

[github-actions]

Are you an Automattician? You can now test your Pull Request on WordPress.com. On your sandbox, run

bin/jetpack-downloader test jetpack update/extensions-description-string

to get started. More details: p9dueE-5Nn-p2

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

• ✅ Include a description of your PR changes.
  
• ✅ All commits were linted before commit.
  
• ✅ Add a "[Status]" label (In Progress, Needs Team Review, ...).
  
• ✅ Add testing instructions.
  
• ✅ Specify whether this PR includes any changes to data or privacy.
  
• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

---

The e2e test report can be found here. Please note that it can take a few minutes after the e2e tests checks are complete for the report to be available.

---

Once your PR is ready for review, check one last time that all required checks (other than "Required review") appearing at the bottom of this PR are passing or skipped.
Then, add the "[Status] Needs Team review" label and ask someone from your team review the code.
Once you’ve done so, switch to the "[Status] Needs Review" label; someone from Jetpack Crew will then review this PR and merge it to be included in the next Jetpack release.

---

Jetpack plugin:

• Next scheduled release: April 4, 2023.
• Scheduled code freeze: March 28, 2023.

[kraftbj]

Marking as Do Not Merge as a bit of a safety check since we're not sold on the advantage of this.

For my sake, I think making the DX worse at the expense of UX is not the way to go. I'd almost say I'd rather us add a notice ("We're aware of the deprecation notice thrown, but we're waiting for a better way of doing this from Core.", for example).

The UX benefits of the status quo include links to support and a richer description overall.
The DX benefit of removing it is just no notices in the console.

I vote to hold on to the status quo as long as possible until the deprecation turns into actually breaking or we have an alternative solution to provide rich content there.

[github-actions]

This PR has been marked as stale. This happened because:

• It has been inactive in the past 3 months.
• It hasn’t been labeled `[Pri] BLOCKER`, `[Pri] High`, etc.

No further action is needed. But it's worth checking if this PR has clear testing instructions, is it up to date with trunk, and it is still valid. Feel free to close this PR if you think it's not valid anymore — if you do, please add a brief explanation.

[jeherve]

Closing for now, we can reopen once we have a decision.