SDK-2411 Update logo/brand lockup in UI

[jhaven-stytch]

Linear Ticket: SDK-2411

Changes:

1. Updates logo file
2. Adds 50% white background behind logo (necessitates wrapping main content area in a new Row composable)
3. Updates B2C UI Workbench activity to avoid insets

Screenshots

B2C

B2B

Notes:

Checklist:

• I have verified that this change works in the relevant demo app, or N/A
• I have added or updated any tests relevant to this change, or N/A
• I have updated any relevant README files for this change, or N/A

[jhaven-stytch]

Looking into why this one UI test is failing. It passes locally, and nothing changed in the semantics, so a little confused why CI is having issues...