feat(accordion): update shape based on parent group shape

Author: brandyscarney

core/src/components/accordion/accordion.ionic.scss

@@ -56,10 +56,18 @@
 }
 
 // Shape only applies when inside an inset accordion group
-:host(.in-accordion-group-expand-inset) ::slotted(ion-item[slot="header"]) {
+:host(.in-accordion-group-expand-inset.in-accordion-group-shape-round) ::slotted(ion-item[slot="header"]) {
   --border-radius: #{globals.$ion-border-radius-400};
 }
 
+:host(.in-accordion-group-expand-inset.in-accordion-group-shape-soft) ::slotted(ion-item[slot="header"]) {
+  --border-radius: #{globals.$ion-border-radius-200};
+}
+
+:host(.in-accordion-group-expand-inset.in-accordion-group-shape-rectangular) ::slotted(ion-item[slot="header"]) {
+  --border-radius: #{globals.$ion-border-radius-0};
+}
+
 // Accordion Content
 // --------------------------------------------------
 

core/src/components/accordion/accordion.tsx

@@ -444,6 +444,9 @@ export class Accordion implements ComponentInterface {
           'accordion-animated': this.shouldAnimate(),
 
           'in-accordion-group-expand-inset': hostContext('.accordion-group-expand-inset', this.el),
+          'in-accordion-group-shape-round': hostContext('.accordion-group-shape-round', this.el),
+          'in-accordion-group-shape-soft': hostContext('.accordion-group-shape-soft', this.el),
+          'in-accordion-group-shape-rectangular': hostContext('.accordion-group-shape-rectangular', this.el),
         }}
       >
         <div