chore: Remove broken testimonials tab from landing page navbar

The testimonials section doesn't exist, so the nav link was non-functional

Author: Programcode

src/components/landing/Navbar.tsx

@@ -8,7 +8,6 @@ const Navbar = () => {
     const navLinks = [
         { href: "#features", label: "Features" },
         { href: "#how-it-works", label: "How It Works" },
-        { href: "#testimonials", label: "Testimonials" },
     ];
 
     return (