Unable to turn off dev mode usage statistics in the browser

[mshabarov]

Description of the bug

The goal is to double-check the opt-out option for Vaadin usage stats, find an issue if any, and fix it.

Then we should document it officially as today the only Java-side opt-out is documented. This is covered by another ticket.

Expected behavior

Vaadin should not send POST requests to usage stats server if stats is disabled.

Versions

• Vaadin / Flow version: 24.9.8, but most likely valid for lots of older versions.

[caalador]

Seems that the clientside does a collection which is sent to the server, but the server doesn't store nor send any of the received dev mode statistics when vaadin.devmode.usageStatistics.enabled=false is set.

So it would seem that we need to get vaadin.statistics.optout flag set to the correct mode (e.g. localStorage.setItem('vaadin.statistics.optout', 'true') for no collection) on init.