core.http Action configuration breaks UI if timeout is entered

Problem

When trying to modify the timeout on the core.http Action configuration page, as soon as you enter in a value into the timeout text field the UI breaks.

Error

TypeError: value.startsWith is not a function
    at ActionsDetails.isExpression (main.js:1:7371)
    at ActionsDetails.render (main.js:1:12925)

Reproduce

Go go /#/actions/core.http and enter in any number into the timeout field.

Thanks for submitting the bug report, @sk8erwitskil!