Fix Issue #2 (stats not working) in New-TicTacToeGame.ps1

[OkeyDokeyGnocchi]

Description

Added logic following stats empty check when running a new game to pull existing stats (if applicable) and verify both players exist in the state file. If not, missing player(s) is/are added and the changes are then committed to the state file.

Related Issue

#2

Motivation and Context

This change allows stats to be saved and recalled in the state file by verifying player exists in the state file when a new game is created. Without this check, end of game results in "The property <insert Wins/Losses/Ties> cannot be found on this object".

How Has This Been Tested?

Changes tested by running new games using 3 accounts in Slack and verifying stats are saved/reported correctly following each game's end using the "stats" command. Tested and verified stats survive server reboot and still report correctly.

Screenshots (if appropriate):

Types of changes

• [ x] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.