Remove global max width

[znicholasbrown]

PR Checklist:

• add a short description of what's changed to the top of the CHANGELOG.md
• add/update tests (or don't, for reasons explained below)

Describe this PR

This PR removes the global max width of 1440px on the critical path (dashboard > flow > flow run > task > task run) to make better use of large monitors. Other pages are untouched at the moment.

Resolves: #1016

[joeclayallday]

Here's another approach if we want to save space. I think your approach makes a ton of sense too & its simpler.