Binding ViewModel params with incorrect keys

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Describe the bug

When a form is posted without any value from a `ViewModel`, every required parameter located in the `VieModel` will bind with incorrect name. Example: A required param located in `ViewModel.ParamA` will incorrectly bind as `ParamA` instead of `ViewModel.ParamA`.

### Expected Behavior

A required parameter located at `ViewModel.ParamA` should always bind with key `ViewModel.ParamA`.

### Steps To Reproduce

In the PageModel:
```
public class MyViewModel
{
[Required]
public string ParamA { get; set; }
[Required]
public string ParamB { get; set; }
}

[BindProperty]
public required MyViewModel ViewModel { get; set; } = new MyViewModel();

[BindProperty]
[Required]
public required string ParamC { get; set; }
```
In the cshtml:
```

```
Posting this form above will **incorrectly** bind with keys `ParamA`, `ParamB` and `ParamC`. You can verify that by looking at the `ModelState`.

Now, if you post the form with at least one input from the `ViewModel`, all params of the `ViewModel` will bind correctly:

```

```
Posting this form above will **correctly** bind all params with keys `ViewModel.ParamA`, `ViewModel.ParamB` and `ParamC`.

### Exceptions (if any)

_No response_

### .NET Version

8.0.200

### Anything else?

```
.NET SDK:
Version: 8.0.200
Commit: 438cab6a9d
Workload version: 8.0.200-manifests.e575128c

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19045
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\8.0.200\

.NET workloads installed:
There are no installed workloads to display.

Host:
Version: 8.0.2
Architecture: x64
Commit: 1381d5ebd2

.NET SDKs installed:
2.1.803 [C:\Program Files\dotnet\sdk]
3.1.101 [C:\Program Files\dotnet\sdk]
8.0.200 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.27 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 8.0.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.27 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.27 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 7.0.16 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
Not set

global.json file:
Not found
```