Mention System.Data.SqlClient rename to Microsoft.Data.SqlClient in docs

### Type of issue

Missing information

### Description

Our application is using procedures executed by EF. While porting from EF6 to EF Core, I've ran into runtime issues with `SqlParameter` being used from EF6 libraries.
It would be nice to mention on this page to rename usings `System.Data.SqlClient` to `Microsoft.Data.SqlClient`. To avoid runtime conflicts.

### Page URL

https://learn.microsoft.com/en-us/ef/efcore-and-ef6/porting/

### Content source URL

https://github.com/dotnet/EntityFramework.Docs/blob/main/entity-framework/efcore-and-ef6/porting/index.md

### Document Version Independent Id

c96b2fcb-8af0-f05b-e188-a6c59dd9f428

### Article author

@JeremyLikness