Add dotnet to task inputs

Trying to migrate CI pipelines to .NET 6 and having issues with dependency check.

```bash
Could not execute .NET AssemblyAnalyzer
```

It seems that it cannot detect the currently installed version of dotnet sdk.

However, if I use the available `--dotnet` CLI argument and specify location of the current dotnet version, it will work fine.

Having this **argument available in the task inputs** would be a workaround, until the .NET6 SDK discovery issue is resolved.

Start by locating the Azure DevOps task-input definition and the handling of the existing --dotnet CLI argument. Add the input so it can provide the current .NET SDK location, then verify that the task uses it for .NET 6 dependency checks.

Written by the indexing model from the issue text.