SEO: Improve Kanvas section headings and image accessibility (#7157)

[megha1807]

Description

This PR improves the SEO of the Kanvas section by:

• Using semantic headings in kanvas-design-hero.js and kanvas-design-integrations.js.
• Removing duplicate text and unnecessary styling changes (keeping only SEO-related updates).
• Improving image accessibility with descriptive alt attributes

Files changed

• src/sections/Kanvas/Kanvas-design/kanvas-design-hero.js
• src/sections/Kanvas/Kanvas-design/kanvas-design-integrations.js

How to test

1. Run the project locally using npm start or npm run develop.
2. Open the page with the Kanvas section.
3. Inspect headings and images to verify semantic structure and accessibility.
4. Optional: Run Lighthouse → SEO audit to confirm improvements.

Related issue

Fixes: #7157

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[github-actions]

🚨 Alert! Git Police! We couldn’t help but notice that one or more of your commits is missing a sign-off. A what? A commit sign-off (your email address).

To amend the commits in this PR with your signoff using the instructions provided in the DCO check.

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[l5io]

🚀 Preview for commit 2172ee9 at: https://69b03ccc866d3b1d4247a2a2--layer5.netlify.app

[leecalcote]

Thanks for working on this, @megha1807

[leecalcote]

Good job on signing your commits.

[l5io]

🚀 Preview for commit 34ae747 at: https://69b04db3dd6b3b26ddf377db--layer5.netlify.app