samples: sensor: qdec: Fix wrong harness

The #73619 which fixes the atmel,sam-tc-qdec sensor implementation
introduced agregression on the sample test removing the harness
console. That changed the test to use the default ztest behaviour
which is incompatible with the test outpout. This restore the
harness to the default console value.

Fixes: #74531

Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>