Fix bug where file vs. remote isn't reseting

Fix bug where file vs. remote isn't reseting

- the devtools iframe was not resetting when going back to File mode
- move logic from profiler.directive to common.directive
- add `iframe` flag to `<sl-pid-selector>`

@seanbrookes please review. Isaac found this bug, its a result of the pid-selector refactoring missing some logic needed for iframe communcation.