[Sprint/RollingRabbit](fix): Blocked channels eternally loading. #2244

Closes #2244 (closed)

Summary

Currently, users on production who have nobody blocked will see an ever-spinning loading icon.

Testing

• Check /settings/blocked-channels
• Observe that when channels are blocked, they are shown, when channels are not blocked, the loading icon does not endlessly display.

Reasoning

I'm throwing an error to end the observable lifecycle. The filter with this approach is redundant.