Add alternative onboarding for interstitial search users

[subsymbolic]

Task/Issue URL: https://app.asana.com/0/inbox/361428290920650/1163294449813158/1165440117435986

Description:
Users may experience our app initially via our new interstitial search screen by launching the widget or future system search box and thus skip our initial in-app onboarding. This PR adds an alternative onboarding experience for these users.

Steps to test this PR:

Test new onboarding:

1. Install the app cleanly
2. Install the widget
3. Launch the app from the widget
4. Note that the interstitial onboarding is displayed and the "m_io_s" pixel fires
5. Press "Show More" and note that more info is displayed and the "m_io_m" pixel fires
6. Press "Hide" and note that less info is displayed and the "m_io_l" pixel fires
7. Press "Got it" and note that the onboarding disappears and the "m_io_d" pixel fires
8. Launch the app from the widget again and note that the onboarding does not appear and none of the above pixels fire
9. Launch the app from the app icon
10. Note that the app is launched WITHOUT the initial onboarding

Test that completing in-app onboarding suppresses interstitial onboarding:

1. Install the app cleanly
2. Launch the app from the app icon and complete the initial onboarding
3. Install the widget
4. Launch the app from the widget
5. Note that the interstitial screen is launched WITHOUT any onboarding

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Internal references:

Software Engineering Expectations
Technical Design Template

[cmonfortep]

Haven't tested this as it's assigned to Craig. But I just left some optional comments. Good work here.

[CDRussell]

Approved; good stuff!

A minor UX feedback: the text wraps in a way that makes it hard to read. Would be nicer if it didn't wrap that line for most layouts, or if there was a break between DuckDuckGo and the next line perhaps. Not a blocker.

[subsymbolic]

@CDRussell great point about the text, I had been overzealous using large margins and max width constraints. I have reduced the margins and this frees up more space on smaller screens while still keeping everything identical on larger screens.