Critical Bug: Bug in the search input

[rohansen856]

##Description
when a user first opens the homepage and taps the search button without inputting any username, it displays profile of a user with username @null.

##Steps to reproduce
go to the site https://githubcrawler.vercel.app/ and press the search button without giving any username input.

##Contribution
Please assign me this issue under GSSOC'2024

[rohansen856]

Please assign me this issue under GSSOC'24. I would like to fix it.