Add explanation for Websocket timeouts.

[balhar-jakub]

Describe your pull request here:
API Mediation Layer from 2.15 supports changing timeouts for Websocket connections. This is documenting how.
The documentation is linked to the issue: zowe/api-layer#2603

List the file(s) included in this PR:
user-guide/api-mediation/configuration-connection-limits

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[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.

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[github-actions]

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[github-actions]

💾 The release label is missing. Add a release: label so your content is published with the correct major Zowe release.

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[github-actions]

💾 The release label is missing. Add a release: label so your content is published with the correct major Zowe release.

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[github-actions]

🚀 Deployed on https://65f17b3131ed30c068a55b61--zowe-docs-master.netlify.app

[pablocarle]

Thank you

[janan07]

Reviewed and edited by doc squad