Bug 2005405 - add isPrivate to send-tab

[mhammond]

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[mhammond]

Part of https://bugzilla.mozilla.org/show_bug.cgi?id=1534148, companion to https://bugzilla.mozilla.org/show_bug.cgi?id=2005404

[skhamis]

Looks good! I think the default with the new params works out nicely. Only one comment but nothing blocking...

Only thing missing is the iOS part of this but I assume you've gotten that covered. r+'d!

[skhamis]

We don't need a #[serde(default)] here right? It looks like we'll just modify the public APIs to default to false but include it