(core) Don't show doc/onboarding tour in embedded mode

Summary:
Tours don't really make sense when you can't see the full interface and document, so they're not shown when the interface style is 'light'.

Discussion: https://grist.slack.com/archives/CDHABLZJT/p1661459343666569?thread_ts=1661183887.200899&cid=CDHABLZJT

Test Plan: Extended nbrowser DocTour test

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D3607

app/client/components/GristDoc.ts

@@ -262,6 +262,10 @@ export class GristDoc extends DisposableWithEvents {
       if (isNarrowScreen()) {
         return;
       }
+      // Only start a tour when the full interface is showing, i.e. not when in embedded mode.
+      if (state.params?.style === 'light') {
+        return;
+      }
       // If we have an active tour (or are in the process of starting one), don't start a new one.
       if (tourStarting || isTourActive()) {
         return;