samples: crypto: Set EC-JPake sample backend tag needed for CI

Set the EC-JPake sample backend tag, which is needed for CI to run it.
This sample was currently not run in CI as a result.

Signed-off-by: Joakim Andersson <joakim.andersson@nordicsemi.no>

samples/crypto/ecjpake/sample.yaml

@@ -3,7 +3,7 @@ sample:
   name: EC J-PAKE example
 tests:
   sample.ecjpake:
-    tags: introduction psa
+    tags: introduction psa oberon
     platform_allow: >
       nrf5340dk_nrf5340_cpuapp
       nrf9160dk_nrf9160 nrf52840dk_nrf52840