Scenario tests for dropped databases on Managed Instance

[v-djnisi]

Description

This are scenario tests for dropped databases. I added test testing gets for dropped databases, as well as update and get for short term retention on dropped databases.

Rest-api-specs: https://github.com/Azure/azure-rest-api-specs/pull/4953

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[dsgouda]

@v-djnisi the rest spec PR is inaccessible, please fix the link

[v-djnisi]

Azure/azure-rest-api-specs/pull/4953

[v-djnisi]

I ran the same command but from ps file, and it somehow worked. Everything should be okay now.

[dsgouda]

Thanks @v-djnisi will approve and merge once the REST spec PR is merged

[v-djnisi]

Rest-api-specs was merged, regenerated synced code and squshed.

[dsgouda]

LGTM