[6.1/6.0] Enable tests for ManagedInstance that require additional permissions for user

[apoorvdeshmukh]

We need to enable these tests once user permission issues are resolved for managed instance tests.
[6.1]

• ConnectionResiliencySPIDTest
• MARS tests
• DistributedTransactionTest

[6.0]

• ConnectionResiliencySPIDTest
• MARS tests