fix(prisma): add removal of custom theme migration

prisma/migrations/20220227012541_removal_custom_themes/migration.sql

@@ -0,0 +1,12 @@
+/*
+  Warnings:
+  - You are about to drop the `Theme` table. If the table is not empty, all the data it contains will be lost.
+*/
+-- DropForeignKey
+ALTER TABLE "Theme" DROP CONSTRAINT "Theme_userId_fkey";
+
+-- AlterTable
+ALTER TABLE "User" ALTER COLUMN "systemTheme" SET DEFAULT E'system';
+
+-- DropTable
+DROP TABLE "Theme";