Draft: Fix snap cycling if length input has focus

[Roy-043]

Snap cycling did not work if the length input box (Draft_Line) had the focus.

Forum topic: https://forum.freecadweb.org/viewtopic.php?f=23&t=60662

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[freecadci]

for feature branch PR_5124. Pipeline #393869211 was triggered at 3cb0f20. All CI branch pipelines.