Improve TSF failure handling (#19965)

An internal AI correctly flagged that we aren't calling
`UnadviseSink()` in case a later `Initialize()` call fails.
We can easily fix this by calling `Uninitialize()`.

src/tsf/Handle.cpp

@@ -14,7 +14,7 @@ Handle Handle::Create()
     handle._impl = new Implementation();
     if (FAILED(handle._impl->Initialize()))
     {
-        delete handle._impl;
+        handle._destroy();
         handle._impl = nullptr;
     }
     return handle;
@@ -32,11 +32,7 @@ void Handle::SetDefaultScopeAlphanumericHalfWidth(bool enable)
 
 Handle::~Handle()
 {
-    if (_impl)
-    {
-        _impl->Uninitialize();
-        _impl->Release();
-    }
+    _destroy();
 }
 
 Handle::Handle(Handle&& other) noexcept :
@@ -94,3 +90,12 @@ bool Handle::HasActiveComposition() const noexcept
 {
     return _impl ? _impl->HasActiveComposition() : false;
 }
+
+void Handle::_destroy() noexcept
+{
+    if (_impl)
+    {
+        _impl->Uninitialize();
+        _impl->Release();
+    }
+}

src/tsf/Handle.h

@@ -51,6 +51,8 @@ namespace Microsoft::Console::TSF
         bool HasActiveComposition() const noexcept;
 
     private:
+        void _destroy() noexcept;
+
         Implementation* _impl = nullptr;
     };
 }