[BUG] Web UI locks up when trying to view large task logs

[thomasmitchell]

Describe the bug
If a job produces a sufficiently long task log, the Web UI will stall and not display the task log. This may also lead to aggressive memory leaks in the browser. I started to see this with a task log that was 6 MB at the time.

To Reproduce
Steps to reproduce the behavior:

1. Start a job that will produce a large task log (fs may do this)
2. Try to view the task log in the Web UI after it has become sufficiently large.
3. Behold

Expected behavior
I wanted to see the task log. Instead, the UI locked up.

Screenshots
If applicable, add screenshots to help explain your problem.

SHIELD versions (please complete the following information):

• SHIELD Core: 8.5.0
• SHIELD CLI: n/a

Browser version(s) (please complete if reporting a web UI bug):

• OS: OS X
• Browser: firefox
• Version: 70

Additional context
Add any other context about the problem here.

This may be caused by the event stream interrupting the display of the task log. I haven't been able to gather evidence on this, as this locks up the inspector in the browser as well.