Fixed typos in sign-up and sign-in messages

Closes #20

🛠️ Fixes Issue: #20

Type of change ✍️

Please delete options that are not relevant.

[x] Bug fix (non-breaking change which fixes an issue)

👨‍💻 Changes proposed:

In this pull request, I have fixed a typo in the message that appears after the successful sign-up process in the app. The typo was located in the file signupwindow.py in the python folder, specifically on line 37. Additionally, I have corrected the typo in the message that appears when a wrong password or username is entered on the sign-in page. This typo was located in the main.pyw file on line 36.

✔️ Check List (Check all the applicable boxes)

[x] My code follows the code style of this project.
[x] This PR does not contain plagiarized content.
[x] The title of my pull request is a short description of the requested changes.
[x] My changes have not introduced any new warnings.
[x] I have conducted a self-review of my code.
[x] I am a participant of SWOC'24.

📷 Screenshots

Before:

After: 1. Sign-up typo fix

2. Sign-in typo fix

pinak22dhir / Python-Gamez-Arena