Downgraded the version of ManagedInstances and DistributedAvailabilit… (Azure#28976)

* Downgraded the version of ManagedInstances and DistributedAvailabilityGroups Api due to .Net Sdk build failures caused by error : MembersMustExist  in these API's

* restored the version of ManagedInstance Api as previous

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Co-authored-by: Ji Wang <[email protected]>

Author: 2 people

specification/sql/resource-manager/readme.md

@@ -1393,7 +1393,7 @@ input-file:
 - ./Microsoft.Sql/preview/2021-05-01-preview/LongTermRetentionManagedInstanceBackups.json
 - ./Microsoft.Sql/preview/2021-05-01-preview/RestorableDroppedManagedDatabases.json
 - ./Microsoft.Sql/preview/2021-05-01-preview/ServerConnectionPolicies.json
-- ./Microsoft.Sql/preview/2023-08-01-preview/DistributedAvailabilityGroups.json
+- ./Microsoft.Sql/preview/2021-11-01-preview/DistributedAvailabilityGroups.json
 - ./Microsoft.Sql/preview/2021-11-01-preview/ServerTrustCertificates.json
 - ./Microsoft.Sql/preview/2021-11-01-preview/EndpointCertificates.json
 - ./Microsoft.Sql/preview/2020-11-01-preview/ManagedDatabaseSensitivityLabels.json