Control the preference to always show the DevTools pages on startup from DevTools

VSCode has custom UX to let users opt into always running the inspector. The problem is it is surfaced before users have actually used the inspector so they aren't sure whether it is valuable. We should surface UX inside the embedded devtools to opt in and out of always showing the embedded devtools.

"You have used the inspector a lot, would you like to always launch it when you open DevTools?"

"You haven't interacted with the inspector in N days, would you like to stop seeing it when you debug a flutter app?"

DevTools server should be driving whether the inspector pages are automatically shown on startup from IDEs. That way DevTools can surface the option to opt in and out of always showing the embedded DevTools on startup.

Downside: weird for an IDE setting to be tracked in DevTools rather than the individual IDES. We could mitigate this if we wanted to get fancy by surfacing UX for this in the IntelliJ and VSCode plugin settings as well as DevTools but I'm not sure the complexity would be worth it.

Bonus points:
Also offer the option of always showing DevTools on startup for command line users. I'd personally like this option but I'm biased.

Inizia dal comportamento del server DevTools per l’avvio di DevTools incorporati, quindi confronta le impostazioni dei plugin VSCode e IntelliJ con il percorso di avvio dalla riga di comando. Definisci come DevTools debba consentire agli utenti di scegliere se attivare o disattivare questa funzionalità in base all’uso dell’inspector e documenta se le impostazioni dell’IDE richiedano anch’esse una UX corrispondente. Il lavoro è completato quando la preferenza di avvio funziona in modo coerente attraverso i punti di ingresso richiesti.

Scritto dal modello di indicizzazione a partire dal testo della issue.