SignTool error when /fd parameter is not provided

### Prerequisites

- [X] I have written a descriptive issue title
- [X] I have searched [issues](https://github.com/cake-build/cake/issues) to ensure it has not already been reported

### Cake runner

Cake Frosting

### Cake version

4

### Operating system

Windows

### Operating system architecture

64-Bit

### CI Server

GitHub Actions

### What are you seeing?

In newer versions of signtool.exe (as of Windows SDK 10.0.20348.0), the digest algorithm parameter (`/fd`) is required when running the `sign` command. Currently, the logic in `SignToolSignRunner` only adds the `/fd` parameter if `DigestAlgorithm` is set to `Sha256`. Now, when the parameter is ommitted signtool.exe generates the error:

```
No file digest algorithm specified. Please specify the digest algorithm with the /fd flag. Using /fd SHA256 is recommended and more secure than SHA1. Calling signtool with /fd sha1 is equivalent to the previous behavior. In order to select the hash algorithm used in the signing certificate's signature, use the /fd certHash option.
```

Which causes the tool to fail.

This also means that explicitly setting the `DigestAlgorithm` to `Sha1` in the settings, still does not resolve the issue.

The docs for signtool.exe have been updated to reflect that the `/fd` parameter is now required:
> Note: An error is generated if the /fd switch is not provided while signing.

https://learn.microsoft.com/en-us/dotnet/framework/tools/signtool-exe#sign-command-options

### What is expected?

`SignToolSignRunner` should always emit the `/fd` parameter since the parameter is now required.

### Steps to Reproduce

Attempt to sign and file without setting the `DigestAlgorithm`:

```
[TaskName("Sign")]
public sealed class SignTask : FrostingTask
{
public override void Run(BuildContext context)
{
var file = new FilePath("SampleApp.exe");
context.Sign(file, new SignToolSignSettings
{
TimeStampUri = new Uri("http://timestamp.digicert.com"),
CertThumbprint = ""
});
}
}

```

### Output log

```

.\build.ps1 --target Sign --verbosity Diagnostic
NuGet Config not specified. Will use NuGet default mechanism for resolving it.
Registering task: Sign
Registering task: Hello
Registering task: World
Registering task: Default

========================================
Sign
========================================
Executing task: Sign
Could not resolve path for tool "signtool.exe" using these directories:
Executing: "C:/Program Files (x86)/Windows Kits/10/bin/10.0.22000.0/x64/signtool.exe" SIGN /t "http://timestamp.digicert.com/" /sha1 "" "C:/Tools/dev/cake/SignToolError/build/SampleApp.exe"
SignTool Error: No file digest algorithm specified. Please specify the digest algorithm with the /fd flag. Using /fd SHA256 is recommended and more secure than SHA1. Calling signtool with /fd sha1 is equivalent to the previous behavior. In order to select the hash algorithm used in the signing certificate's signature, use the /fd certHash option.
An error occurred when executing task 'Sign'.
Completed in 00:00:00.0968934
Error: Cake.Core.CakeException: SignTool SIGN: Process returned an error (exit code 1).
at Cake.Core.Tooling.Tool`1.ProcessExitCode(Int32 exitCode)
at Cake.Core.Tooling.Tool`1.Run(TSettings settings, ProcessArgumentBuilder arguments, ProcessSettings processSettings, Action`1 postAction)
at Cake.Core.Tooling.Tool`1.Run(TSettings settings, ProcessArgumentBuilder arguments)
at Cake.Common.Tools.SignTool.SignToolSignRunner.Run(IEnumerable`1 assemblyPaths, SignToolSignSettings settings)
at Cake.Common.Tools.SignTool.SignToolSignAliases.Sign(ICakeContext context, IEnumerable`1 assemblies, SignToolSignSettings settings)
at Cake.Common.Tools.SignTool.SignToolSignAliases.Sign(ICakeContext context, FilePath assembly, SignToolSignSettings settings)
at SignTask.Run(BuildContext context) in C:\Tools\dev\cake\SignToolError\build\Program.cs:line 36
at Cake.Frosting.FrostingTask`1.Cake.Frosting.IFrostingTask.RunAsync(ICakeContext context)
at Cake.Core.CakeTask.Execute(ICakeContext context)

```

Locate the SignToolSignRunner implementation and inspect how it adds arguments when SignToolSignSettings.DigestAlgorithm is unset or set to Sha1. Reproduce the failing sign invocation from the issue, then verify that the generated command always includes the /fd value and that signing no longer fails because the parameter is missing.

Written by the indexing model from the issue text.