Disable the update checker in the playground or compat tests

theatre/devEnv/definedGlobals.ts

@@ -1,3 +1,7 @@
+/**
+ * @see `../globals.d.ts` for the types of these globals
+ * TODO make the globals typesafe
+ */
 export const definedGlobals = {
   'process.env.THEATRE_VERSION': JSON.stringify(
     require('../studio/package.json').version,
@@ -5,4 +9,5 @@ export const definedGlobals = {
   // json-touch-patch (an unmaintained package) reads this value. We patch it to just 'Set', becauce
   // this is only used in `@theatre/studio`, which only supports evergreen browsers
   'global.Set': 'Set',
+  'process.env.BUILT_FOR_PLAYGROUND': JSON.stringify('false'),
 }