Fix Vercel build failures in ETL blog image resolution

[Copilot]

Description

This PR addresses recurring Vercel build failures in the ETL blog PR caused by unresolved local asset paths in a case-sensitive build environment. It normalizes image references in the blog content and updates social image metadata to a valid static path.

Type of Change

• New feature (e.g., new page, component, or functionality)
• Bug fix (non-breaking change that fixes an issue)
• UI/UX improvement (design, layout, or styling updates)
• Performance optimization (e.g., code splitting, caching)
• Documentation update (README, contribution guidelines, etc.)
• Other (please specify):

Changes Made

• Asset path normalization (case-sensitive safe)
  • Replaced broken ./img/... markdown references with the correct ./Img/... paths in blog/ETL-pipeline-tutorial/index.md.
• Metadata image path correction
  • Updated og:image and twitter:image values to /img/blogs/adf-cover_image.png to use a resolvable static asset path.
• Build blocker removed
  • Eliminates unresolved-image failures from Docusaurus/Vercel build for this post.

- ![...](./img/adf-pipeline-overview.png)
+ ![...](./Img/adf-pipeline-overview.png)

- content: "./img/adf-cover_image.png"
+ content: "/img/blogs/adf-cover_image.png"

Dependencies

• No new dependencies.
• No version or configuration changes.

Checklist

• My code follows the style guidelines of this project.
• I have tested my changes across major browsers and devices
• My changes do not generate new console warnings or errors .
• I ran npm run build and attached screenshot(s) in this PR.
• This is already assigned Issue to me, not an unassigned issue.