Issue Summary

This is reproducible on Data Center: (yes) 

There is no possibility to create a hidden issue link type using this API: https://developer.atlassian.com/cloud/jira/platform/rest/v3/api-group-issue-link-types/#api-rest-api-3-issuelinktype-post

Steps to Reproduce

1. Create a hidden issue link type

Expected Results

Should be a parameter in this API POST /rest/api/3/issueLinkType which set the issue hidden type or not.
The hidden issue link type should be visible by all APIs that return the Issue link type, e.g:

GET /rest/api/3/issueLinkType/{issueLinkTypeId}

GET /rest/api/3/issueLinkType

and others.

The hidden issue link should not be visible through the UI.

Actual Results

No possible to create a hidden issue link type

Workaround

Using the entity properties: https://developer.atlassian.com/cloud/jira/platform/jira-entity-properties/