Once the active Prisma client is in the disconnected state, every DB call
raises ClientNotConnectedError. The reconnect machinery was supposed to
recover from this, but _get_engine_pid() inspected the broken client via
prisma's _engine property, which re-raises that same error, so
recreate_prisma_client failed before it could build a replacement client
and the proxy looped on failed reconnects forever (issue #28322 showed
1486+ consecutive failures over 30 days with zero recoveries)
Guard both _get_engine_pid implementations with is_connected() so a
disconnected client reads as "no engine" (pid 0) and the recreate path
proceeds to construct and connect a fresh client
* ensure original client is disconnected when re-creating
* test_recreate_prisma_client_successful_disconnect
* test_recreate_prisma_client_successful_disconnect
