Build.ps1 list that it imports aliases that it does not

It is indicated that build.ps1 loades aliases that it should not (see the line with `Set-SamplerTaskVariable`).

```
Importing tasks from module Sampler
Loading Build-Module.ModuleBuilder.build.Sampler.ib.tasks...
Loading ChocolateyPackage.build.Sampler.ib.tasks...
Loading Clean.ModuleBuilder.build.Sampler.ib.tasks...
Loading DeployAll.PSDeploy.build.Sampler.ib.tasks...
Loading DscResource.Test.build.Sampler.ib.tasks...
Loading generateHelp.PlatyPS.build.Sampler.ib.tasks...
Loading GuestConfig.build.Sampler.ib.tasks...
Loading Invoke-Pester.pester.build.Sampler.ib.tasks...
Loading JaCoCo.coverage.build.Sampler.ib.tasks...
Loading release.module.build.Sampler.ib.tasks...
Loading Set-BuildEnvironment.BuildHelpers.build.Sampler.ib.tasks...
Loading Set-SamplerTaskVariable...
```

This line should be moved down to the `ForEach` so it only lists the aliases it does import.

https://github.com/gaelcolas/Sampler/blob/d19ef072498ac9df81a3839b0b7a502a066f2235/build.ps1#L285