Add Workaround for JWT Refresh Token

[balhar-jakub]

Describe your pull request here:
The documented way to provide the configuration for enabling JWT Token Refresh doesn't work

List the file(s) included in this PR:
docs/user-guide/api-mediation/configuration-jwt.md

After creating the PR, follow the instructions in the comments.

[github-actions]

😺 Thank you for creating this PR! To publish your content to Zowe Docs, follow these required steps.

• Add the label review: doc.
• Identify your content topic with a label. (Examples: area: apiml, area: cli, area: install and config, etc.)
• Specify the major Zowe release(s) for your content. (Examples: release: V1, release: V2, release: V3)
  • If adding content that needs to be removed from V3 documentation, add the V3 N/A tag.
• Select the master branch if your PR updates content that is on the live site. Select docs-staging if your PR updates content for a future release.
• Notify the Doc Squad about this PR. If you don't know whom should review your content, message the #zowe-doc Slack channel. If you know which Doc Squad writer should approve your content, add that person as a reviewer.

Need help? Contact the Doc Squad in the #zowe-doc Slack channel.

[github-actions]

📁 The PR description is missing the file name(s) for the updated content. List all the files included in this PR so this information displays in our Zowe Docs GitHub Slack channel.

If you have addressed this issue already, refresh this page in your browser to remove this comment.

[github-actions]

🚀 Deployed on https://65fc1de07fcad400937edd81--zowe-docs-master.netlify.app

[janan07]

Reviewed and edited by doc squad