fix: added hover effect on Sponsorship prospectus button in about section

[ARsenic100]

This PR adds hover effect on Sponsorship prospectus button in about section. This hover effect is same as the hover effect on the city buttons that are not speaker city in speaker section.

Fixes #617

Screen.Recording.2025-03-13.051750.mp4

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[Jaishree2310]

@ARsenic100 Read the contribution guidelines thoroughly before opening a PR .
Only open a PR after receiving approval from the project maintainers

[ashmit-coder]

@ARsenic100 Read the contribution guidelines thoroughly before opening a PR . Only open a PR after receiving approval from the project maintainers

@Jaishree2310 there is no need to go around in every pr and leave comments to the contributors, giving feedback is good, but just making mundain comments will not increase your chances of selection.

[Jaishree2310]

@ARsenic100 Read the contribution guidelines thoroughly before opening a PR . Only open a PR after receiving approval from the project maintainers

@Jaishree2310 there is no need to go around in every pr and leave comments to the contributors, giving feedback is good, but just making mundain comments will not increase your chances of selection.

Hi, I was reviewing PRs to explore different types of issues and understand how they are being resolved. My goal was to learn from the process and gain insights into effective problem-solving.