fix(ui5-combo-box): use value when first selecting an item with value

Author: nikoletavnv

packages/main/src/ComboBox.ts

@@ -1373,9 +1373,9 @@ class ComboBox extends UI5Element implements IFormInputElement {
 		}
 
 		this.value = this._selectedItemText;
-		// On first item select the _useSelectedValue is still false. 
-		// In case the item has a value property, we set the _useSelectedValue to true to start working with the value instead with the text
-		if (!this._useSelectedValue && item.value != undefined) {
+		// On first item select the _useSelectedValue is still false.
+		// In case the item has a value property, we set the _useSelectedValue to true to start working with the value instead with the text.
+		if (!this._useSelectedValue && item.value !== undefined) {
 			this._useSelectedValue = true;
 		}