Added Remove Subject option in Grade Calculator

[dadigavasavipriya]

Fixes Issue🛠️

Closes #1002

Description👨‍💻

Added Remove Subject option in Absolute Grade Calculator and changed marks input format

Type of change📄

• New feature (non-breaking change which adds functionality)

How this has been tested✅

I have tested in my own local host.

Checklist✅

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added demonstration in the form of GIF/video file
• I am an Open Source Contributor

Screenshots/GIF📷

bandicam.2024-06-06.16-01-15-769.mp4

@Rakesh9100 please review the changes, and please review this pull request. Please let me know any changes required. Thank you, once again, for assigning me this issue

[github-actions]

Hey @dadigavasavipriya, Welcome to the project CalcDiverse! 🎊
Thanks for your contribution! Your effort makes this project better. Keep it up! 🙌
Please wait for the PR to be reviewed. Happy Coding!! ✨

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[dadigavasavipriya]

I noticed there are conflicts in the files Calculators/Grade-Calculator/script.js and Calculators/Grade-Calculator/style.css that need to be resolved. Can I address this and proceed with creating a new pull request.