Blockquote + Line Separator: Incorrectly removal of Style

[jleandroperez]

Steps:

1. Launch the Empty Editor
2. Insert a Blockquote
3. Type 1 + Shift + Enter + 2
4. Press Arrow Down
5. Hit delete TWO times

As a result, the number 2 will be removed. But the number 1 will remain onscreen, and it'll loose it's Blockquote Style (while preserving the indentation), as seen below.

Expected: After deleting the number 2, the number 1 should preserve it's style.

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