Add a Boolean for has output to improve front end loading

[hulto]

the issue
currently the front end has to load the entire output of a task before it can determine if output exists to render the badge. This can be slow when tasks have a lot of output.

Describe the solution you'd like
Add a Boolean field to the task entity "has_output" which is updated when output is sent. This will make the front end queries more efficient and readable.

Describe alternatives you've considered

• Checking for nil or "" doesn't seem to work reliably.
• comparing updated, and seen at is kinda hacky and unreliable.

Additional context
Na