Check for ModulePrefix parameter presence instead of it being a dynamic parameter

[anamnavi]

For Publish-PSResource declare ModulePrefix as a regular parameter instead of a dynamic parameter. This allows for better error message writing and error handling with regards to how this parameter works with repositories.

PR Summary

PR Context

Resolves #1827 #1806

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: or [ WIP ] to the beginning of the title (the WIP bot will keep its status check at Pending while the prefix is present) and remove the prefix when the PR is ready.
• Breaking changes
  • None
  • OR
  • Documentation needed
    • Issue filed:
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed
    • Issue filed:
• Testing - New and feature
  • N/A or can only be tested interactively
  • OR
  • Make sure you've added a new test if existing tests do not effectively test the code changed
• Tooling
  • I have considered the user experience from a tooling perspective and don't believe tooling will be impacted.
  • OR
  • I have considered the user experience from a tooling perspective and enumerated concerns in the summary.

[alerickson]

What does "can remove if Repository is 'Mandatory' parameter" mean? What's being removed?

[anamnavi]

I just meant if we make the -Repository parameter mandatory for Publish-PSResource then I'll remove the check for seeing if Repository was included in the cmdlet invocation because that condition is guaranteed.

[anamnavi]

@EmilienCourt please track this in favor of #1865