[Route] Update PSSO local account URL in routes (#45143)

Updated the URL for the PSSO local account guide to include the platform
SSO section.

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**Related issue:** Resolves #30674 

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## Summary by CodeRabbit

* **Bug Fixes**
* Improved navigation shortlink to direct users to a more specific
section on the setup guide page.

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website/config/routes.js

@@ -1276,7 +1276,7 @@ module.exports.routes = {
   'GET /learn-more-about/generate-fleets-agent': 'https://fleetdm.com/guides/enroll-hosts#ui',
   'GET /learn-more-about/certificates': '/guides/connect-end-user-to-wifi-with-certificate',
   'GET /learn-more-about/enrollment-profiles': 'https://developer.apple.com/documentation/devicemanagement/profile?changes=l_11_5',
-  'GET /learn-more-about/psso-local-account': '/guides/setup-experience',
+  'GET /learn-more-about/psso-local-account': '/guides/setup-experience#platform-sso',
   'GET /learn-more-about/deploy-fleet': '/docs/deploy/deploy-fleet',
   'GET /learn-more-about/vulnerability-exposure-cves': 'https://github.com/fleetdm/fleet/blob/1ea1fddfd62f66fd14de65cbeceb4f7a9d0167ec/server/chart/internal/mysql/charts.go#L111-L138',