Disable analytics when running DevTools from `devtools_tool serve`

Right now we disable analytics for non-release builds, but to build DevTools with the devtools server we have to build the DevTools app in release mode (at least right now). This can cause analytics events to be sent from DevTools when we are developing, which is not what we want.

When we run from `devtools_tool serve` we should be able to pass an argument through somehow to disable analytics.