Lighthouse. Fix accessibility and SEO problems with Slider on Community page

[natanchik]

📝 Describe the refactoring task

There are some accessibility and SEO problems with Slider on Community page:

• Image elements do not have alt attributes;
• Lists contain elements other than li elements and script and template elements;
• Uses ARIA roles on incompatible elements;

📍 Code location

🛠️ Suggested improvement

Fix accessibility and SEO problems with Slider on Community page.

ℹ️ Additional context

✅ Definition of Done (DoD):

Accessibility and SEO problems with Slider on Community page are resolved.