Connect Four asks for CPU input in single-player mode #574

Describe the bug

Choosing one player starts the two-player loop. After the first legal move, the game prompts the user to enter a move for CPU.

To reproduce

1. Run python "Connect Four/connectfour.py".
2. Choose 1 player and enter a name such as Ada.
3. Enter a legal column such as 4.
4. The next prompt asks for CPU's input.

Expected behavior

Single-player mode should use the existing computer-turn loop so the CPU chooses its own column.

Proposed fix

Call gamePlayOnePlayer from the one-player branch and leave the two-player branch unchanged.