Dragging a block causes it to receive passive focus

[BenHenning]

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Description

When dragging a block with the mouse (or keyboard navigation's move mode), the block being moved will appear to have both passive focus and selection simultaneously.

Reproduction steps

1. Open the keyboard navigation test environment.
2. Navigate to a movable block.
3. Attempt to move it either with 'M' and arrow keys or via the mouse.
4. Observe that its border is dashed (passive focus) and thicker (selected).

Stack trace

Screenshots

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[BenHenning]

Fixed in RaspberryPiFoundation/blockly#9034.