19571 empty lines in text frames

[Thomas-Ganter]

Resolves: #19571

Empty lines were ignored when applying format changes.
This change now makes sure that empty lines now will be included in updates.
This resolves the odd behavior of scaling text boxes that contain empty lines.

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• I created a unit test or vtest to verify the changes I made (if applicable)

[Thomas-Ganter]

Type 30 in Size ...

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Tests still all work.
Feels like it can be merged.

[Thomas-Ganter]

@cbjeukendrup does there seem to be something missing or preventing the merge?