Description

BraveFirstRunFlowSequencer does not seem to be used in any meaningful way. The class is a thin wrapper around Chromium's FirstRunFlowSequencer.

It's currently used in two places: WelcomeOnboardingActivity and BraveVpnSupportActivity.

In both places, it does nothing: there's a callback onFlowIsKnown(boolean isChild) and we ignore the boolean completely.

Currently, the sequencer only delays initializeViews() (the method called when the callback is fired) until the account/child-status checks finish; it does not influence which onboarding steps run or any prefs.

Given the current code, we can remove BraveFirstRunFlowSequencer completely and simply call initializeViews() directly (in both WelcomeOnboardingActivity and BraveVpnSupportActivity) and the behavior would be the same, just without that async wait.
The sequencer looks like an old refuse pattern copied from the standard FRE rather than a requirement.