chore(deps): update dependency microsoft.data.sqlclient to 6.1.2 (#3229)

This PR contains the following updates:

| Package | Change | Age | Confidence |
|---|---|---|---|
| [Microsoft.Data.SqlClient](https://aka.ms/sqlclientproject)
([source](https://redirect.github.com/dotnet/sqlclient)) | `6.1.1` ->
`6.1.2` |
[![age](https://developer.mend.io/api/mc/badges/age/nuget/Microsoft.Data.SqlClient/6.1.2?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|
[![confidence](https://developer.mend.io/api/mc/badges/confidence/nuget/Microsoft.Data.SqlClient/6.1.1/6.1.2?slim=true)](https://docs.renovatebot.com/merge-confidence/)
|

---

### Release Notes

<details>
<summary>dotnet/sqlclient (Microsoft.Data.SqlClient)</summary>

###
[`v6.1.2`](https://redirect.github.com/dotnet/sqlclient/blob/HEAD/CHANGELOG.md#Stable-Release-612---2025-10-07)

This update brings the below changes over the previous stable release:

##### Fixed

- Fixed an issue where initializing PerformanceCounters would throw
`System.InvalidOperationException`
[#&#8203;3629](https://redirect.github.com/dotnet/sqlclient/pull/3629)
- Fixed an issue where a Custom SqlClientAuthenticationProvider was
being overwritten by default implementation.
[#&#8203;3651](https://redirect.github.com/dotnet/SqlClient/pull/3651)
- Fixed a concurrency issue in connection pooling where the number of
active connections could be lower than the configured maximum pool size.
[#&#8203;3653](https://redirect.github.com/dotnet/SqlClient/pull/3653)

</details>

---

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Author: renovate-bot

cloud-sql/sql-server/CloudSql.csproj

@@ -6,7 +6,7 @@
 
   <ItemGroup>
     <PackageReference Include="Google.Cloud.Diagnostics.AspNetCore3" Version="5.3.0" />
-    <PackageReference Include="Microsoft.Data.SqlClient" Version="6.1.1" />
+    <PackageReference Include="Microsoft.Data.SqlClient" Version="6.1.2" />
     <PackageReference Include="Polly" Version="8.6.4" />
   </ItemGroup>