Allow metric dashboards to have no owner, in case the user gets deleted

Author: matt-aitken

internal-packages/database/prisma/migrations/20260211120000_make_metrics_dashboard_owner_nullable/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable: make ownerId nullable to match ON DELETE SET NULL foreign key
+ALTER TABLE "public"."MetricsDashboard" ALTER COLUMN "ownerId" DROP NOT NULL;

internal-packages/database/prisma/schema.prisma

@@ -2559,8 +2559,8 @@ model MetricsDashboard {
   projectId String?
 
   /// Who created the dashboard
-  owner   User   @relation(fields: [ownerId], references: [id], onDelete: SetNull, onUpdate: Cascade)
-  ownerId String
+  owner   User?   @relation(fields: [ownerId], references: [id], onDelete: SetNull, onUpdate: Cascade)
+  ownerId String?
 
   createdAt DateTime @default(now())
   updatedAt DateTime @updatedAt