[nrf fromlist] samples: drivers: i2c: rtio_loopback: change harness to console

The harness was set to ztest, but the sample requires the console
harness to match on the "sample complete" line, its not actually
using ztest.

Upstream PR #: 86098

Signed-off-by: Bjarki Arge Andreasen <[email protected]>

Author: bjarki-andreasen

samples/drivers/i2c/rtio_loopback/sample.yaml

@@ -5,9 +5,12 @@ tests:
     tags:
       - rtio
       - i2c_target
-    harness: ztest
+    harness: console
     harness_config:
       fixture: i2c_bus_short
+      type: one_line
+      regex:
+        - "sample complete"
     platform_allow:
       - b_u585i_iot02a
       - nrf5340dk/nrf5340/cpuapp