docs: update manage-refresh-tokens-actions.mdx

[nick-gagliardi]

Description

api.refreshToken.setExpiresAt cannot increase the lifetime of the refresh token.

Per the product team:

The RT part of the API does indeed have the same limitation that tokens can only have their lifetime shortened and not increased.

Confirmed with Sessions team that setIdleExpiresAt has the same limitation.

References

https://auth0.slack.com/archives/CMXHR8NK1/p1771530182638949

https://auth0team.atlassian.net/browse/DOCS-4603

https://auth0team.atlassian.net/browse/ESD-43736

Checklist

• [ x] I've read and followed CONTRIBUTING.md.
• [ x] I've tested the site build for this change locally.
• [ x] I've made appropriate docs updates for any code or config changes.
• [ x] I've coordinated with the Product Docs and/or Docs Management team about non-trivial changes.

[github-actions]

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