InstallHelper should not inherit from PSCmdlet

[alyssa1303]

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest released version
• Search the existing issues.

Steps to reproduce

In InstallHelper.cs on line 30, it inherits from PSCmdlet. This is incorrect because it's a class that contain functionality, not the cmdlet itself.
It should also not throw terminating errors or write errors.

Expected behavior

InstallHelper doesn't inherit from PSCmdlet and doesn't throw terminating errors or write errors from that class.

Actual behavior

InstallHelper inherits from PSCmdlet and throws terminating errors or write errors from that class.

Error details

No response

Environment data

ModuleType Version    PreRelease Name                                PSEdition ExportedCommands
---------- -------    ---------- ----                                --------- ----------------
Script     2.2.5                 PowerShellGet                       Desk      {Find-Command, Find-DSCResource, Find-Module, Find-RoleCapability…}

Name                           Value
----                           -----
PSVersion                      7.2.5
PSEdition                      Core
GitCommitId                    7.2.5
OS                             Microsoft Windows 10.0.19044
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}       
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Visuals

No response