Repo Gardening: do not add label to assigned issues

[jeherve]

Fixes Automattic/studio#1012

Proposed changes:

Until now, when a PR was opened to close a specific issue, the assignIssues task did 2 things:

1. Assign the issue to the person working on the PR, to indicate to everyone following the issue that it is being worked on, and to hold the person opening the PR accountable.
2. Add the "[Status] In Progress" label to indicate that the issue is being worked on.

With the GitHub UI improvements in the past few years, PRs opened to close a specific issue are a lot more visible than they once were. The "In Progress" label is consequently not that useful anymore. Let's remove it.

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

• Disable "[Status] In Progress" Github action labeling studio#1012
• p1741202034661009-slack-C06DRMD6VPZd

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

• No

Testing instructions:

• Merge this PR into your trunk branch locally, and push that version of trunk to a fork of this repo.
• Create an issue in your fork.
• Open a PR that makes a change, and includes "Fixes #xxx" in the PR description.
• Observe that you get automatically assigned to the issue, but no progress label is added.

[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.
  
• ✅ Add a "[Status]" label (In Progress, Needs Review, ...).
  
• ✅ Add a "[Type]" label (Bug, Enhancement, Janitorial, Task).
  
• ✅ 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 🤖

---

Follow this PR Review Process:

1. Ensure all required checks appearing at the bottom of this PR are passing.
2. Make sure to test your changes on all platforms that it applies to. You're responsible for the quality of the code you ship.
3. You can use GitHub's Reviewers functionality to request a review.
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If you have questions about anything, reach out in #jetpack-developers for guidance!

[anomiex]

🤷 I see you can search with linked:pr to find issues that have an associated PR. I don't know whether anyone is using [Status] In Progress manually as well as automatically such that they might find this useful. But if they do, we could always revert this.