Update First Run install process

[krschau]

Summary of the pull request

Simplify the process for installing the widget service on Windows 10 to mimic what we already do on Windows 11.

References and relevant issues

#2191

Detailed description of the pull request / Additional comments

On Windows 11 (already):

1. We assume the package is there
2. On navigation to Dashboard, we ensure it's there and if not, send the user to the store

On Windows 10 (as of this change):

1. On first launch of Dev Home, install the widget service from the store
2. On navigation to Dashboard, we ensure it's there and if not, send the user to the store

This fixes the bug where we would re-install on every launch.

Validation steps performed

PR checklist

• Closes On Windows 10, Dev Home does its first initialization check on each launch #2191
• Tests added/passed
• Documentation updated