Add new setting modeling.highlightEdges (#2166)

* Add doc comment to getThemeColorForEngine

* Add a user-level setting for highlightEdges

* Add a custom settings action to update the edge line visibility

* Make the settings pane always open to user settings first

* Refactor engineConnectionMananer.start() to take a settings object

* Revert alway open user settings

* Set highlight edges on engine start up

* fmt fml

* Fix tsc error

src/lib/testHelpers.ts

@@ -99,7 +99,6 @@ export async function executor(
     width: 0,
     height: 0,
     executeCode: () => {},
-    theme: Themes.Dark,
     makeDefaultPlanes: () => {
       return new Promise((resolve) => resolve(defaultPlanes))
     },