fix(sheet): sheet.flange refuses rule values instead of ignoring them (#570) (#594)

sheet.flange refuses the sheet values its rule owns (thickness, K-factor, bend radius, reliefs, hem gap) instead of silently ignoring them, and says to use a rule. Un-ignores the #570 regression test. Fixes #570.

Co-authored-by: jonaswre <jonas.wrede@beyondit.gmbh>

crates/engine/src/cmd/sheet_tests.rs

@@ -2562,7 +2562,6 @@ fn flat_pattern_reports_a_round_hole_as_a_circle() {
 }
 
 #[test]
-#[ignore = "fails until #570 is fixed"]
 fn a_flange_asked_for_0_8_mm_is_0_8_mm_or_refused_never_silently_2_5_mm() {
     // `thickness` on sheet.flange may become an inline override of the rule, or be refused as
     // an unknown parameter; either is fine. Building the default 2.5 mm sheet silently is not.