tests: Disable SSF if interface is mocked

The test uses SSF interface mock instead, so disable the SSF to avoid
two implementations of the same interface.

Ref: NCSDK-31359

Signed-off-by: Tomasz Chyrowicz <[email protected]>

Author: tomchy

tests/subsys/dfu/dfu_target/suit/boards/nrf54h20dk_nrf54h20_cpuapp.conf

@@ -8,3 +8,6 @@
 CONFIG_LOG=y
 CONFIG_LOG_BACKEND_UART=y
 CONFIG_LOG_MODE_DEFERRED=y
+
+# Disable SUIT SSF service and use mocks instead
+CONFIG_SSF_SUIT_SERVICE_ENABLED=n