(core) Polish telemetry code

Summary: Also fixes a few small bugs with telemetry collection.

Test Plan: Server and manual tests.

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D3915

app/server/lib/DocApi.ts

@@ -906,6 +906,7 @@ export class DocWorkerApi {
                 name: tutorialTrunk.name,
                 options: {
                   tutorial: {
+                    ...tutorialTrunk.options?.tutorial,
                     // For now, the only state we need to reset is the slide position.
                     lastSlideIndex: 0,
                   },