Allow `$PSCmdlet` methods in constrained language

Summary of the new feature / enhancement

The following fails when using constrained language mode:

function Test-ShouldProcess {
     [CmdletBinding(SupportsShouldProcess, ConfirmImpact = 'High')]
     param()

     if($PSCmdlet.ShouldProcess('something')) {
         return $true
     }
}

Error:

Cannot invoke method. Method invocation is supported only on core types in this language mode.

Other usages are also blocked, such as getting preference variables from caller scope within modules:

  param (
    $VerbosePreference = $PSCmdlet.GetVariableValue('VerbosePreference')
  )

Proposed technical implementation details (optional)

No response

首先在受限语言模式下重现 ShouldProcess 和 GetVariableValue 示例，然后跟踪受限语言中的方法调用处理。定义允许使用的 $PSCmdlet 方法，并验证这些调用能够正常工作，同时不放宽对其他方法调用的限制。