Placeholder trimmed when movableBlocks prop is active

[mogavin]

Expected Behavior

In empty editor, the first block has a text placeholder.

Current Behavior

When prop movableBlocks is active, this placeholder is trimmed.

Steps to Reproduce

1. Render a MegadraftEditor component with prop movableBlocks with true value;
2. Note in first block that text placeholder is trimmed ( show only the first letter ).