ENHANCED_KEY flag missing when releasing RightAlt

### Windows Terminal version

current main

### Windows build number

10.0.19045.4894

### Other Software

_No response_

### Steps to reproduce

1. Run the following c++ code:
```c++
#include
#include
int main()
{
INPUT_RECORD rec;
DWORD count;
while (true)
{
::ReadConsoleInputW(::GetStdHandle(STD_INPUT_HANDLE), &rec, 1, &count);
if (rec.EventType == KEY_EVENT)
{
std::cout << "type: KEY_EVENT" << std::hex
<< ", down: " << rec.Event.KeyEvent.bKeyDown
<< ", ENHANCED_KEY: " << !!(rec.Event.KeyEvent.dwControlKeyState & ENHANCED_KEY)
<< ", ctrl: 0x" << rec.Event.KeyEvent.dwControlKeyState
<< ", vcod: 0x" << rec.Event.KeyEvent.wVirtualKeyCode
<< ", scod: 0x" << rec.Event.KeyEvent.wVirtualScanCode
<< ", wchr: 0x" << rec.Event.KeyEvent.uChar.UnicodeChar << '\n';
}
}
}
```
2. Press LeftCtrl key, press RightCtrl key, check ENHANCED_KEY flag.
3. Press LeftAlt key, press RightAlt key, check ENHANCED_KEY flag.

### Expected Behavior

The ENHANCED_KEY flag is present when RightAlt is pressed and released.

The current conhost.exe is not affected by this issue.

### Actual Behavior

The ENHANCED_KEY flag is absent when RightAlt is released, but is present when RightAlt is pressed.

Start by tracing Windows Terminal's handling of KEY_EVENT records and the ENHANCED_KEY state for RightAlt, using the provided ReadConsoleInputW reproduction program. Compare the release event with conhost.exe behavior; done means ENHANCED_KEY is present when RightAlt is both pressed and released.

Written by the indexing model from the issue text.