fix: add clearing of combobox on Backspace or Delete key press (#2816)

…gle-selection mode

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## Description:
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Closes: #2785
## Definition of Reviewable:
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---------

Co-authored-by: Mojsoski, Blagoja (UIS) <blagoja.mojsoski@union-investment.de>

Author: balco0110

.changeset/some-beers-live.md

@@ -0,0 +1,5 @@
+---
+'@solid-design-system/components': minor
+---
+
+Add clearing of `sd-combobox` on Backspace or Delete key press

packages/components/src/components/combobox/combobox.ts

@@ -449,6 +449,11 @@ export default class SdCombobox extends SolidElement implements SolidFormControl
       return;
     }
 
+    if (!this.multiple && (event.key === 'Backspace' || event.key === 'Delete')) {
+      this.clearCombobox();
+      return;
+    }
+
     // Handle enter.
     if (event.key === 'Enter') {
       const currentOption = this.getCurrentOption();