Fix ef migrations

[dkurepa]

#6239
In #6225 we updated Microsoft.Data.SqlClient from 6.1.4 to 7.0.1, which had a breaking change. This should fix it

Testing in https://dev.azure.com/dnceng/internal/_build/results?buildId=2961486&view=results

[Copilot]

Pull request overview

This PR addresses a breaking change introduced by upgrading Microsoft.Data.SqlClient to 7.0.1 (in #6225) by ensuring the Azure/Entra authentication extensions are available and updating managed identity credential construction to the newer Azure.Identity API.

Changes:

• Add Microsoft.Data.SqlClient.Extensions.Azure so SqlClient’s Entra authentication flows work (notably for EF migrations).
• Update managed identity credential creation to use ManagedIdentityId APIs (SystemAssigned / FromUserAssignedClientId).
• Bump supporting dependency versions (Azure.Identity and a few Microsoft.Extensions.* patch versions) to satisfy the new auth stack.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Maestro/Maestro.Data/Maestro.Data.csproj	Adds SqlClient Azure extensions package needed for Entra/MI authentication scenarios (including EF migrations).
src/Maestro/Maestro.Common/AzureDevOpsTokens/AzureDevOpsTokenProvider.cs	Switches managed identity credential creation to ManagedIdentityId-based constructors.
src/Maestro/Maestro.Common/AppCredentials/CredentialResolver.cs	Updates managed identity credential creation to the new Azure.Identity API surface.
src/Maestro/Maestro.Common/AppCredentials/AppCredential.cs	Updates MI credential creation used for client assertion flows to the new Azure.Identity API surface.
Directory.Packages.props	Central package updates: bumps Azure.Identity, adds Microsoft.Data.SqlClient.Extensions.Azure, and updates a few Microsoft.Extensions.* patch versions.