fix: add index to AssignmentReason (#18520)

packages/prisma/migrations/20250108095727_assignment_reason_index/migration.sql

@@ -0,0 +1,2 @@
+-- CreateIndex
+CREATE INDEX "AssignmentReason_bookingId_idx" ON "AssignmentReason"("bookingId");

packages/prisma/schema.prisma

@@ -1711,6 +1711,8 @@ model AssignmentReason {
   booking      Booking              @relation(fields: [bookingId], references: [id], onDelete: Cascade)
   reasonEnum   AssignmentReasonEnum
   reasonString String
+
+  @@index([bookingId])
 }
 
 enum EventTypeAutoTranslatedField {