fix: remove the @unique from the prisma schema

prisma/migrations/20260311154019_remove_openid_unique/migration.sql

@@ -0,0 +1,2 @@
+-- DropIndex
+DROP INDEX "TikTokToken_openId_key";

prisma/schema.prisma

@@ -23,7 +23,7 @@ model TikTokToken {
   id           String   @id @default(cuid())
   userId       String   @unique
   user         User     @relation(fields: [userId], references: [id], onDelete: Cascade)
-  openId       String   @unique
+  openId       String
   accessToken  String
   refreshToken String
   expiresAt    DateTime