Fix remove network

[JohnReedV]

Description

Adds logic to unstake any accounts staked to a subnet on deregistration

Related Issue(s)

• Closes #564

Type of Change

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation update
• [ ] Other (please describe):