Add NestJS icon to Backend Development

[abhijeetBhale]

What type of PR is this? (check all applicable)

• Bug Fix

Description

This PR adds the missing NestJS icon to the skills section of the GitHub Profile README Generator.

The NestJS icon was previously unavailable in the UI, which affected the visual output for users including NestJS in their skillset.
This update includes:

• Integration of the NestJS SVG icon sourced from Devicon.
• Updates to the relevant skills/icon mapping logic to include NestJS.

Related Tickets & Documents

No existing issue linked, but addresses a minor gap in icon coverage for backend frameworks.

QA Instructions, Screenshots, Recordings

1. Navigate to the Skills section in the generator.
2. Select NestJS from the list of technologies.
3. Confirm that the NestJS icon now appears correctly in the preview panel and is reflected in the generated markdown.

Screenshot (if applicable):
Add a screenshot of the preview section with the NestJS icon if you have one.

Added to documentation?

• No documentation changes needed.