Unsupported Block Editor partially obscures the block toolbar

[dcalhoun]

Describe the bug
The Unsupported Block Editor (UBE) partially obscures the block toolbar on certain screen sizes, making certain block actions impossible—e.g., adding rows to a Table block.

Originally reported by a user: 8970561-zd-a8c

To Reproduce
Steps to reproduce the behavior:

1. In a WPCOM site, create a post in a web browser containing a Table block.
2. Open the same post with the mobile block editor.
3. Tap the unsupported block to edit it with the UBE.
4. Focus the block within the UBE.

Expected behavior
All block toolbar actions are accessible.

Screenshots

Smartphone (please complete the following information):

• Device: Samsung Galaxy S20
• OS: Android 13
• Version: 25.4

Additional context
The UBE is only accessible to sites with a Jetpack connection.