fix: accessibility issue on the Welcome page

[shrilakshmishastry]

Description

Fix accessibility issues on the Welcome page:

• use button tag for collection instead of div
• hide decorative images for assistive technology
• give meaningful labels to links in the Links section

Accessibility tree structure

then	now

issue link : accessibility issue

Contribution Checklist:

• [x] The pull request only addresses one issue or adds one feature.
• [x] The pull request does not introduce any breaking changes
• [x] I have added screenshots or gifs to help explain the change if applicable.
• [x] I have read the contribution guidelines.
• [x] Create an issue and link to the pull request.