chore: remove obsolete polywork icon

[mroderick]

What does this PR change? What problem does it solve?

The service has been shutdown as of 2025-01-31 and is no more. There is no need to keep the icon around anymore.

See https://deepnewz.com/startups/polywork-irish-startup-backed-stripe-collison-brothers-to-shut-down-560973fe

The ploywork entry in https://github.com/adityatelange/hugo-PaperMod/wiki/Icons#social-icons can also be removed.

Was the change discussed in an issue or in the Discussions before?

No.

PR Checklist

• This change adds/updates translations and I have used the template present here.
• I have enabled maintainer edits for this PR.
• I have verified that the code works as described/as intended.
• This change adds a Social Icon which has a permissive license to use it.
• This change does not include any CDN resources/links.
• This change does not include any unrelated scripts such as bash and python scripts.
• This change updates the overridden internal templates from HUGO's repository.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud