fix: Dangling references after element disconnect (#608)

Several components did not call the parent `disconnectedCallback`,
preventing triggering `hostDisconnected`
for any controllers (theming in this case) and
leading to a memory leak.

Co-authored-by: Simeon Simeonoff <sim.simeonoff@gmail.com>

src/components/checkbox/checkbox-base.ts

@@ -141,6 +141,7 @@ export class IgcCheckboxBaseComponent extends EventEmitterMixin<
 
   public override disconnectedCallback() {
     this.removeEventListener('keyup', this.handleKeyUp);
+    super.disconnectedCallback();
   }
 
   protected handleKeyUp() {

src/components/radio/radio.ts

@@ -130,6 +130,7 @@ export default class IgcRadioComponent extends EventEmitterMixin<
 
   public override disconnectedCallback() {
     this.removeEventListener('keyup', this.handleKeyUp);
+    super.disconnectedCallback();
   }
 
   protected handleKeyUp() {

src/components/select/select-group.ts

@@ -43,6 +43,7 @@ export default class IgcSelectGroupComponent extends IgcDropdownGroupComponent {
 
   public override disconnectedCallback() {
     this.observer.disconnect();
+    super.disconnectedCallback();
   }
 
   protected override getParent() {

src/components/slider/slider-base.ts

@@ -267,6 +267,7 @@ export class IgcSliderBaseComponent extends LitElement {
 
   public override disconnectedCallback() {
     this.removeEventListener('keyup', this.handleKeyUp);
+    super.disconnectedCallback();
   }
 
   protected handleKeyUp() {