Structure member alignment issues in WTSApi32

[rosenqui-cysiv]

Describe the bug
The timestamp fields in the WTSINFO and WTSINFOEX_LEVEL1 end up with bad values because their offsets within the structure aren't correct. This is due to the SizeConst = USERNAME_LENGTH + 1 of the previous field in WTSINFO messing up the padding. I haven't fiddled with WTSINFOEX_LEVEL1 but I believe it has similar issues.

Changing WTSINFO to use SizeConst = USERNAME_LENGTH + 2 or adding a private char _padding field after UserName fixes it.

What code is involved
PInvoke\WTSApi32\WTSApi32.cs

Expected behavior
The timestamp fields should have either 0s or sane values. The CurrentTime field should always be sane.

Repro

if (WTSEnumerateSessionsEx(HWTSSERVER.WTS_CURRENT_SERVER_HANDLE, out var sessionList)) {
    foreach (var session in sessionList) {
        if (WTSQuerySessionInformation(HWTSSERVER.WTS_CURRENT_SERVER_HANDLE, session.SessionId, WTS_INFO_CLASS.WTSSessionInfo, out var pSessionInfo, out var bytesReturned)) {
            using (pSessionInfo) {
                var sessionInfo = pSessionInfo.ToStructure<WTSINFO>(bytesReturned);
                Console.WriteLine("CurrentTime is {0}", sessionInfo.CurrentTime.ToDateTime());
            }
        }
    }
}

[NN---]

Also using FILETIME instead of LARGE_INTEGER in WTSINFO definition is not correct.

https://devblogs.microsoft.com/oldnewthing/20040825-00/?p=38053

[NN---]

Seems like this is the real issue here.
Will submit PR with a test.