## Issue Addressed
This PR addresses issue https://github.com/sigp/lighthouse/issues/4350
## Proposed Changes
This change will enable slasher broadcast in the following cases:
No flag is passed,
`--slasher-broadcast` is passed and,
`--slasher-broadcast=true` is passed.
Only when an explicit false value is passed the slasher does not broadcast.(`--slasher-broadcast=false`).
## Additional Info
TODO
- [x] Modify CLI parsing logic
- [x] Write test
Refer to #4353
Co-authored-by: Rahul Dogra <rahulcooldogra@gmail.com>
Co-authored-by: Gua00va <105484243+Gua00va@users.noreply.github.com>