In bug 1933744 we prevented SessionStore from reopening a saved tab group into a private window. In bug 1946761 we prevented users from saving tab groups from a private window. The general design principle has been to prevent tab group information leaking between private and non-private windows.
ActionsProviderTabGroups already respected privacy through the implementation of `Tabbrowser.getAllTabGroups`, but `SessionStore.getSavedTabGroups` doesn't respect privacy. Perhaps it should. But in any case, this patch ensures that search results in private windows don't include saved tab groups.
Differential Revision: https://phabricator.services.mozilla.com/D248351
5b3f57be44