fix: update theme.scss to agree with Angular material v15 theming

Refs #659

src/theme.scss

@@ -183,7 +183,18 @@ $nghyd-warn:    mat.define-palette($mat-irstea-prune);
 $nghyd-error:   mat.define-palette($mat-irstea-rouille);
 // $nghyd-warn:    mat-palette($mat-irstea-rouille);
 
-$nghyd-theme: mat.define-light-theme($nghyd-primary, $nghyd-accent, $nghyd-warn);
+// $nghyd-theme: mat.define-light-theme($nghyd-primary, $nghyd-accent, $nghyd-warn);
+
+  
+$nghyd-theme: mat.define-light-theme((
+        color: (
+          primary: $nghyd-primary,
+          accent: $nghyd-accent,
+          warn: $nghyd-warn
+        ),
+        typography: mat.define-typography-config(),
+        density: 0
+       ));
 
 @include mat.all-legacy-component-themes($nghyd-theme);