Build fails of `$(AndroidManifest)` is an absolute path

### Android framework version

net8.0-android, net9.0-android

### Affected platform version

All

### Description

Context: https://developercommunity.visualstudio.com/t/Error-code---XA1018--Specified-AndroidMa/10728496

`dotnet build` fails if `$(AndroidManifest)` is an absolute path.

This is likely related to:

https://github.com/dotnet/android/blob/df68c208ad02d09ebb9e6a87053343985dfc1e36/src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets#L572

### Steps to Reproduce

```dotnetcli
% dotnet new android

# this works
% dotnet build *.csproj

# this fails
% dotnet build "-p:AndroidManifest=$(pwd)/AndroidManifest.xml" *.csproj
…
error XA1018: Specified AndroidManifest file does not exist: $(pwd)/$(pwd)/AndroidManifest.xml.
```

### Did you find any workaround?

Don't use an absolute path in `$(AndroidManifest)`.

### Relevant log output

_No response_