Request ESR backport: Allow granular API keys access to about.json

@supermathie @awesomerobot

Following up on the closed topic API user with granular access cannot read about.json | Discourse MCP

ESR users who want to use the Discourse MCP server with least-privilege security on login-required sites are currently blocked. The fix allows granular API keys to access /about.json and is in main/stable (v2026.4.0+) but not in ESR.

Could PR #38948 be backported to ESR?

PR #38948: DEV: allow granular api keys access to about.json - Pull Request #38948 - discourse/discourse - GitHub

FYI esr is about to get a release I think?