Terminal receives focus on drag n drop (#20003)

### Summary
Updates terminal to gain foreground focus when a user drags and drops a
file into the terminal.

### Changes
Updates the `DragDropHandler` to call `SetForegroundWindow`.

### Validation
* Built and deployed locally
* Manually verified terminal gains focus when dragging and dropping

Closes #19934

Author: etbala

src/cascadia/TerminalControl/TermControl.cpp

@@ -3073,6 +3073,11 @@ namespace winrt::Microsoft::Terminal::Control::implementation
             co_return;
         }
 
+        if (const auto hwnd = reinterpret_cast<HWND>(OwningHwnd()))
+        {
+            SetForegroundWindow(hwnd);
+        }
+
         const auto weak = get_weak();
 
         if (e.DataView().Contains(StandardDataFormats::ApplicationLink()))

src/interactivity/win32/windowproc.cpp

@@ -951,6 +951,11 @@ LRESULT Window::_HandleGetDpiScaledSize(UINT dpiNew, _Inout_ SIZE* pSizeNew) con
 // - <none>
 void Window::_HandleDrop(const WPARAM wParam) const
 {
+    if (const auto hwnd = GetWindowHandle())
+    {
+        SetForegroundWindow(hwnd);
+    }
+
     const auto drop = reinterpret_cast<HDROP>(wParam);
     Clipboard::Instance().PasteDrop(drop);
     DragFinish(drop);