Documentation: Upgrade instructions need to be updated to call out using the managed solution zip

Description

Upgrade instructions - https://github.com/microsoft/Power-CAT-Copilot-Studio-Kit/blob/main/INSTALLATION_INSTRUCTIONS.md#upgrading-existing-solution

These state:
6. Select CopilotStudioKit.zip

However, on the releases page, you provide both the managed and unmanaged solution for download.

The instructions need to be updated to call out using the "CopilotStudioKit_XXXXXXX_managed.zip" file instead. Otherwise on import you get this warning:
"The solution is already installed on this system as a managed solution and the package supplied is attempting to install it in unmanaged mode. Import can only update solutions when the modes match. Uninstall the current solution and try again."

I understand that the section above upgrade/install for the download does call out to grab the managed version, but the instructions should be updated to match and be consistent. Especially since from the release page, if you click upgrade instructions, it jumps directly to that section, and users may not see the download note.

Optionally I would recommend move upgrading to its own .md file, then point back to install configurations steps if they are identical.

Steps to reproduce

1. have managed solution installed
2. try to update to unmanaged version

Expected behavior

Consistent messaging/wording through documentation.

Actual behavior

Instructions as written lead to an error.

Environment

No response

Additional context or logs

No response