flow-manager: move time check after RUNNNING state change

flow-manager: move time check after RUNNNING state change

When running in pcap-file mode and with a continous directory
reading, the provided directory can be empty.
By having no packets and being in offline mode, the initial packet timestamp
is never set. However, Flow Manager waited until the timestamp was set
to proceed with transferring its state to "RUNNING".
Other pcap-related threads (RX / workers) are set in RUNNING state while
waiting for the PCAP to appear in the directory.

As a result, the main Suricata-Main thread timed out after the default
60 seconds budget for threads to turn from INIT_DONE to RUNNING state.

Ticket: 7568