Improve bp landscape with shorter content.

1. Fix Left layout by adding abs()
2. If there is only one-line title, show shorter two-pane layout as
   https://screenshot.googleplex.com/7vbrL85irnwtLjh

After-fix screenshot:
- oneline title: https://screenshot.googleplex.com/6q5ea3w7KYcoRhe
- longer content: https://screenshot.googleplex.com/6YmNeMuekALufk9

Flag: com.android.systemui.constraint_bp
Bug: 335278136
Test: check on test app
Test: atest PromptViewModelTest
Change-Id: Iedbfc39d9ba4260f74d36b0c451ba62123a5c411