Overwrite FocusAsync in FluentAutoComplete (#4230)

Co-authored-by: Vincent Baaij <vnbaaij@outlook.com>

Author: MarvinKlein1508

examples/Demo/Shared/Microsoft.FluentUI.AspNetCore.Components.xml

@@ -6227,6 +6227,12 @@
         <member name="M:Microsoft.FluentUI.AspNetCore.Components.FluentAutocomplete`1.MustBeClosed">
             <summary />
         </member>
+        <member name="M:Microsoft.FluentUI.AspNetCore.Components.FluentAutocomplete`1.FocusAsync">
+            <inheritdoc />
+        </member>
+        <member name="M:Microsoft.FluentUI.AspNetCore.Components.FluentAutocomplete`1.FocusAsync(System.Boolean)">
+            <inheritdoc />
+        </member>
         <member name="T:Microsoft.FluentUI.AspNetCore.Components.HeaderFooterContent`1">
             <summary />
         </member>

src/Core/Components/List/FluentAutocomplete.razor.cs

@@ -706,6 +706,32 @@ private bool MustBeClosed()
 
         return false;
     }
+
+    /// <inheritdoc />
+    public override void FocusAsync()
+    {
+        if (Multiple)
+        {
+            Element?.FocusAsync();
+        }
+        else
+        {
+            OnDropDownExpandedAsync();
+        }
+    }
+
+    /// <inheritdoc />
+    public override void FocusAsync(bool preventScroll)
+    {
+        if (Multiple)
+        {
+            Element?.FocusAsync(preventScroll);
+        }
+        else
+        {
+            OnDropDownExpandedAsync();
+        }
+    }
 }
 
 /// <summary />