Revert "Drop old TaskRunCounter table (not used anymore)"

This reverts commit d7311a3.

Author: matt-aitken

packages/database/prisma/migrations/20240523082748_drop_old_task_run_counter_table/migration.sql

@@ -1731,6 +1731,12 @@ model TaskRunDependency {
   updatedAt DateTime @updatedAt
 }
 
+/// deprecated, we hadn't included the project id in the unique constraint
+model TaskRunCounter {
+  taskIdentifier String @id
+  lastNumber     Int    @default(0)
+}
+
 /// Used for the TaskRun number (e.g. #1,421)
 model TaskRunNumberCounter {
   id String @id @default(cuid())