SQL Server managed identity authentication instead of secrets

[v-ajajvanu]

Description

Made changes to support Managed Identity Authentication for SQL Server DB instead of using Secrets.

Related issues

Addresses [issue 122770].

Testing

Tested by creating FHIR service instance using the updated ARM template.
Validated different settings after deployments.
Executed CRUD operations on FHIR service instance.
Executed Export operation on FHIR service instance.

FHIR Team Checklist

• Update the title of the PR to be succinct and less than 65 characters
• Add a milestone to the PR for the sprint that it is merged (i.e. add S47)
• Tag the PR with the type of update: Bug, Build, Dependencies, Enhancement, New-Feature or Documentation
• Tag the PR with Open source, Azure API for FHIR (CosmosDB or common code) or Azure Healthcare APIs (SQL or common code) to specify where this change is intended to be released.
• Tag the PR with Schema Version backward compatible or Schema Version backward incompatible or Schema Version unchanged if this adds or updates Sql script which is/is not backward compatible with the code.
• CI is green before merge
• Review squash-merge requirements

Semver Change (docs)

Patch|Skip|Feature|Breaking (reason)

[mikaelweave]

Hi @v-ajajvanu, we have a PR below that I think already does this using a user assigned managed identity. Can you see if this is similar?

#3946

[v-ajajvanu]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[v-ajajvanu]

@mikaelweave Indeed, the changes in this PR and the ones in PR #3946 are comparable. The only thing that was different was that we were utilizing a system-assigned identity, designating it as the primary user for SQL Server, and modifying the connection string in Key Vault to switch the authentication property to "Active Directory Managed Identity" and delete the user ID and password.

This PR is no longer required because the modifications indicated in PR 3946 have already been merged into the main branch.

Kindly refrain from merging this PR's changes.