Update use-the-centralized-deployment-powershell-cmdlets-to-manage-ad…

[msbemba]

…d-ins.md

Added PS steps to install the module before importing

Fixes https://github.com/MicrosoftDocs/microsoft-365-docs-pr/issues/23600

[msbemba]

@JohanFreelancer9 Please copy review

[learn-build-service-prod[bot]]

Learn Build status updates of commit 1478bb3:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
microsoft-365/enterprise/use-the-centralized-deployment-powershell-cmdlets-to-manage-add-ins.md	:white_check_mark:Succeeded

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel

[yogkumgit]

@kelleyvice-msft Please merge this PR. Thanks

[yogkumgit]

@kelleyvice-msft Gentle reminder.