Implement join game function

[Benjtalkshow]

closes #80

1 - join game function

Implemented a join game function which checks if the game with the given game_id is in a waiting state. Then adds the player's username to the appropriate color slot in the game state and If all required players have joined, it changes the game status from "Waiting" to "Ongoing".

2 - join game function test

Implemented test cases for the join game function which includes:

1. Verifying that players can successfully join a game using different colors.
2. Checks that the player's username is correctly added to the game state.
3. Ensures the game status remains "Waiting" while players are joining.
4. Confirms the game status changes to "Ongoing" when all required players have joined.

[princeibs]

@Benjtalkshow are you having any challenge completing this?
You can also ping the StarkLudo Contributors channel on Telegram if you need more clarity on this issue.

[Benjtalkshow]

@Benjtalkshow are you having any challenge completing this? You can also ping the StarkLudo Contributors channel on Telegram if you need more clarity on this issue.

Yea just chatted you few min ago with handle Kitch. I am working on it.

[princeibs]

• Please fix failing contract CI and client CI

[Benjtalkshow]

@princeibs
Will make my final PR soon sir

[princeibs]

Please fix failing CI