fix(template): fix on widget settings saving

[gaetanDev7]

SUP-2270

When settings like icon on the widget's header and "Collapsed by default" option are change, it also trigger the "save" function ref to change .

change from :

save({ imageId: debouncedImageId, useGreyScale, useBlur, blur });

to :

save((currentProperties) => ({ ...currentProperties, imageId: debouncedImageId, useGreyScale, useBlur, blur }));

npx create-lumapps-extension@xxxx my-widget