Fix onboarding dialog when onBackPressed()

[nalcalag]

Task/Issue URL: https://app.asana.com/0/488551667048375/1207453843423106/f

Description

Hide onboarding dialog when back pressed

Steps to test this PR

• [x] Fresh install
• [x] Go to browser
• [x] Navigate to a site
• [x] Check onboarding dialog appears
• [x] Go back
• [x] Check dialog is gone
• [x] Go forward
• [x] Check dialog works as expected

No UI changes

[nalcalag]

• #4606 👈
• develop

This stack of pull requests is managed by Graphite. Learn more about stacking.

Join @nalcalag and the rest of your teammates on Graphite