Fix spelling of "on-premises"

[CollinAlpert]

Initially I set out to fix the spelling of "on-premises" in https://learn.microsoft.com/en-us/connectors/webcontentsv2/ however those docs don't seem to be on GitHub. If somebody could fix that spelling as well, I would be eternally grateful.

[learn-build-service-prod]

Learn Build status updates of commit ee71da6:

✅ Validation status: passed

File	Status	Preview URL	Details
power-platform/admin/power-automate-licensing/types.md	✅Succeeded
power-platform/admin/security/overview.md	✅Succeeded
power-platform/admin/test-connection-exchange-server-onpremises.md	✅Succeeded

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[Mattp123]

@CollinAlpert - Thank you for your contribution. The article has been revised to remove the incorrect instances for the term "on-premises."
Closing without merging.