[Twinsen] [0.17.74] Blueprints do not save empty value

[Calibretto22]

Game 0.17.74, Vanilla

TestSetup:
- a rail-chain-signal alongside a rail.
- chain-signal is connected to the ciruit-network (green wire, see screenshot).
- output-signals are configured to be empty (with right click)
- a blueprint of this setup does not replicate the settings

Bug:
- when building the blueprint the default-values are put into the empty fields
- empty fields are not saved in blueprints

Expectation:
- the null-values should be saved in the blueprint, because they are a setting the player made

Possible solutions:
- save null-values in blueptins
- save deviations from defaults (where default != empty)

TestBlueprint:
0eNqdlE1vgzAMhv+Lz0kFtKVdjrvsvts0VYiCRS1BgkKoVlX570vSD3WDSssukRL8PvaLnZxh347Ya5IGxBmoUnIA8XmGgRpZtv7MnHoEAWSwAway7PxOl9SCZUCyxi8Qqd0xQGnIEF70YXMq5NjtUbuAu3IwTtscDA8IBr0anEpJn8qRMgYnEHxlLZtAsh/peXUoSfJroRNQslhfUOli7Qp1xiRW/vvgA1K/NBpRPlZLNYiV3dm55MtIB9kcZHWHdFjT2HFsXVGaKt6rFqcsnt1cJE9daKx/e8h9O2bdZU/crePcJXOM/D/tyW6+jFZtscdDeSSlr74KNZp+NMVkGI+kzRiwt6pDBH/3M6l0KRuM1n54bfhp0dI3L/UXKVr5CvbvbX02mpu45s1O5jaO4e6nG7HwJoiHJ4TBEfUQgjfLJN2+5HmSbqz9Br1YfFY=

[Twinsen]

Fixed in Version: 0.17.77.

Also fixed it for normal rail signals and roboports.

Thanks for the report.