Update EditForm examples in Forms article 8.0

### Description

Remove `method="post"` from all `EditForm` occurrences.

### Page URL

https://learn.microsoft.com/en-us/aspnet/core/blazor/forms/?view=aspnetcore-7.0

### Content source URL

https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/blazor/forms/index.md

### Document ID

d6347620-1029-3051-7ecd-673641cdde22

### Article author

guardrex