Update GroupCreationEnabled parameter on Set-OwaMailboxPolicy.md

[dariomws]

https://github.com/MicrosoftDocs/office-docs-powershell/issues/5263

I have verified this in Outlook for Windows, Outlook Mobile for Android and Outlook on the Web.

[opbld30]

Docs Build status updates of commit c10f266:

🕙 Full build: the average full build time is 12 min(s) 46 sec(s), this is based on the last 1000 build(s) for this repository.

[opbld34]

Docs Build status updates of commit c10f266:

✅ Validation status: passed

File	Status	Preview URL	Details
exchange/exchange-ps/exchange/client-access/Set-OwaMailboxPolicy.md	✅Succeeded	View (exchange-ps)

For more details, please refer to the build report.

Note: If you changed an existing file name or deleted a file, broken links in other files to the deleted or renamed file are listed only in the full build report.

[opbld31]

Docs Build status updates of commit 56771db:

🕙 Full build: the average full build time is 12 min(s) 46 sec(s), this is based on the last 1000 build(s) for this repository.

[opbld34]

Docs Build status updates of commit 56771db:

✅ Validation status: passed

File	Status	Preview URL	Details
exchange/exchange-ps/exchange/client-access/Set-OwaMailboxPolicy.md	✅Succeeded	View (exchange-ps)

For more details, please refer to the build report.

Note: If you changed an existing file name or deleted a file, broken links in other files to the deleted or renamed file are listed only in the full build report.