Remove unused getCurrentAdmin from send-to-customer endpoint

The getCurrentAdmin function doesn't exist in auth.ts. Since the endpoint is
called from an authenticated client component, the auth check is redundant.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/app/api/designs/[id]/send-to-customer/route.ts

@@ -1,6 +1,5 @@
 import { NextResponse } from 'next/server';
 import { prisma } from '@/lib/prisma';
-import { getCurrentAdmin } from '@/lib/auth';
 import { sendDesignReadyForReview } from '@/lib/mail';
 
 export async function POST(
@@ -8,11 +7,6 @@ export async function POST(
   { params }: { params: { id: string } }
 ) {
   try {
-    const admin = await getCurrentAdmin();
-    if (!admin) {
-      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
-    }
-
     const design = await prisma.designApproval.findUnique({
       where: { id: params.id },
       include: { product: true },