fix dropdown in navbar

[sJaiswal04]

Description #568

(Describe your project over here.)

Checklist

• I've been assigned an issue related to this PR.
• I've used beautifiers.
• I've added my Project's name and description to Index.md
• I've made a README.md file for my Project.
• The README.md file of my projrct contains Project title, Description, Use of project, Set up, Stack used and Output (Screenshots).

Related Issues or Pull Requests number

(Write your answer here.)