Update "Product/#Working with Figma" (#12823)

Additional step when duplicating starter file. There's no way to set
public visibility by default. So we need to ensure that each file is
visible to anyone with the link.

# Checklist for submitter

If some of the following don't apply, delete the relevant line.

- [ ] Changes file added for user-visible changes in `changes/` or
`orbit/changes/`.
See [Changes
files](https://fleetdm.com/docs/contributing/committing-changes#changes-files)
for more information.
- [ ] Documented any API changes (docs/Using-Fleet/REST-API.md or
docs/Contributing/API-for-contributors.md)
- [ ] Documented any permissions changes
- [ ] Input data is properly validated, `SELECT *` is avoided, SQL
injection is prevented (using placeholders for values in statements)
- [ ] Added support on fleet's osquery simulator `cmd/osquery-perf` for
new osquery data ingestion features.
- [ ] Added/updated tests
- [ ] Manual QA for all new/changed functionality
  - For Orbit and Fleet Desktop changes:
- [ ] Manual QA must be performed in the three main OSs, macOS, Windows
and Linux.
- [ ] Auto-update manual QA, from released version of component to new
version (see [tools/tuf/test](../tools/tuf/test/README.md)).

handbook/product/README.md

@@ -35,6 +35,7 @@ At Fleet, like [GitLab](https://about.gitlab.com/handbook/product-development-fl
 When starting a new draft:
 
 - Create a new file inside the [Fleet product](https://www.figma.com/files/project/17318630/%F0%9F%94%9C%F0%9F%93%A6-Fleet-EE%C2%AE-(product)?fuid=1234929285759903870) project by duplicating "\[TEMPLATE\] Starter file" (pinned to the top of the project).
+- Right-click on the duplicated file, select "Share", and ensure **anyone with the link** can view the file.
 - Rename each Figma file to include the number and name of the corresponding issue on the [drafting board](https://app.zenhub.com/workspaces/-product-backlog-coming-soon-6192dd66ea2562000faea25c/board). (e.g. # 11766 Instructions for Autopilot enrollment).
 -  The starter file includes 3 predefined pages: Cover, Ready, and Scratchpad.
     -  **Cover.** This page has a component with issue number, issue name, and status fields. There are 3 statuses: Work in progress, Approved, and Released (the main source of truth is still the drafting board).