Replaced concurrentSessions by concurrentSession

As documented in Cyberark API v2 documentation the field is "concurrentSession" and not "concurrentSessions"

Allow concurrent sessions

Replaced "concurrentSessions" by "concurrentSession"

CyberArk internal issue link: []()

Replace concurrentSessions by concurrentSession

[ ] The CHANGELOG has been updated, or
[x] This PR does not include user-facing changes and doesn't require a CHANGELOG update

[x] This PR includes new unit and integration tests to go with the code changes, or
[ ] The changes in this PR do not require tests

[ ] Docs (e.g. READMEs) were updated in this PR
[ ] A follow-up issue to update official docs has been filed here: [insert issue ID]()
[x] This PR does not require updating any documentation

[ ] This PR changes product behavior and has been reviewed by a PO, or
[ ] These changes are part of a larger initiative that will be reviewed later, or
[x] No behavior was changed with this PR

[ ] Security architect has reviewed the changes in this PR,
[ ] These changes are part of a larger initiative with a separate security review, or
[x] There are no security aspects to these changes

cyberark / ansible-security-automation-collection