tests: Fix ospfapi client to clear ospf process

Test is failing locally:
2023-09-06 18:39:56,865 DEBUG: r1: vtysh result:
        Hello, this is FRRouting (version 9.1-dev).
        Copyright 1996-2005 Kunihiro Ishiguro, et al.

        r1# conf t
        r1(config)# router ospf
        r1(config-router)# ospf router-id 1.1.1.1
        For this router-id change to take effect, use "clear ip ospf process" command
        r1(config-router)#
2023-09-06 18:39:56,865 DEBUG: root: GOT LINE: 'SUCCESS: 1.0.0.0'
2023-09-06 18:39:56,866 DEBUG: root: GOT LINE: '2023-09-06 18:39:55,982 INFO: TESTER: root: Waiting for 1.1.1.1'
2023-09-06 18:39:56,867 DEBUG: root: GOT LINE: '2023-09-06 18:39:55,982 DEBUG: TESTER: root: expected '1.1.1.1' != '1.0.0.0''
2023-09-06 18:39:56,867 DEBUG: root: GOT LINE: 'waiting on notify'

Sure looks like the router-id is not allowed to be changed because
neighbors have already been formed.  If we are changing the router-id
then let's clear the process to allow it to correctly change.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

tests/topotests/ospfapi/test_ospf_clientapi.py

@@ -218,10 +218,12 @@ def _test_router_id(tgen, testbin):
 
         step("router id: check for modified router id")
         r1.vtysh_multicmd("conf t\nrouter ospf\nospf router-id 1.1.1.1")
+        r1.vtysh_multicmd("clear ip ospf process")
         _wait_output(p, "SUCCESS: {}".format(waitlist[1]))
 
         step("router id: check for restored router id")
         r1.vtysh_multicmd("conf t\nrouter ospf\nospf router-id 1.0.0.0")
+        r1.vtysh_multicmd("clear ip ospf process")
         _wait_output(p, "SUCCESS: {}".format(waitlist[2]))
     except Exception as error:
         logging.error("ERROR: %s", error)