ASP0018 analyzer does not respect FormatFilterAttribute for {format} route parameter

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Describe the bug

When route uses parameter `{format}` and the method is marked with `FormatFilterAttribute`, the ASP0018 analyzer claims a parameter is unused.

### Expected Behavior

The ASP0018 analyzer should not generate the warning

### Steps To Reproduce

Having method like this in controller:

```CSharp
[FormatFilter]
[HttpGet("items.{format}")]
public async Task> ExportItems()
{
...
}
```

### .NET Version

.NET 8

### Anything else?

May be related to #54212