Instructions for manual OPA download point to old README

[schrolla]

Prerequisites

• This issue has an informative and human-readable title.

ScubaGear Version

1.5.0

Operating System

Windows 11

PowerShell Version

5.1

M365 Environment and License(s)

N/A

🐛 Summary

When using Initialize-SCuBA, if there is an error downloading OPA and installing it automatically, the cmdlet notes the error and provides a message with a pointer to the ScubaGear documentation that shows how to install OPA manually (see screenshot). The reference to the documentation is "Unable to download OPA executable. To try manually downloading, see details in README under 'Download the required OPA executable'`." However, the documentation no longer has that section in the latest version directly in the README.
Originally noted in user report #1630.

Steps to reproduce

1. Install ScubaGear v1.5.0 from PSGallery
2. Disable connection to internet or block access to OPA website
3. Run Initialize-SCuBA without a connection to the internet
4. Note manual OPA install warning message

Expected behavior

The reference provided in the error message should accurately point the user to the relevant documentation for manually installing OPA.

Output from Initialize-SCuBA (optional)

[schrolla]

Note to descope another issue out of Nemo of similar size/priority.