fix: crash in SelectField.setValue() with an undefined value

refs #609

src/app/formulaire/elements/select/select-field.ts

@@ -80,6 +80,7 @@ export abstract class SelectField extends Field {
             const valueChanged = (
                 (previousSelectedEntry === undefined && v !== undefined)
                 || (
+                    previousSelectedEntry !== undefined && v !== undefined &&
                     !Array.isArray(previousSelectedEntry)
                     && !Array.isArray(v)
                     && previousSelectedEntry.id !== v.id