Update azure-arc-enable-cluster.md

[zaidmohd]

Update "az containerapps" to "az containerapp" command. I think it's a typo.

[prmerger-automator[bot]]

@zaidmohd : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[opbld31]

Learn Build status updates of commit bacb098:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
articles/container-apps/azure-arc-enable-cluster.md	:white_check_mark:Succeeded

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[Jak-MS]

@cebundy

• Can you review this PR?
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#label:"aq-pr-triaged" @MicrosoftDocs/public-repo-pr-review-team

[ShannonLeavitt]

This change has been applied in the live article. I'll close the PR now. Thanks!