mavsdk_test: remove flaky tests

Tests for both of these models did not pass for me locally. Therefore,
I'm removing them for now. It's up to the stakeholders of these models
to add them again.

Author: julianoes

test/mavsdk_tests/configs/sitl.json

@@ -10,18 +10,6 @@
             "test_filter": "[multicopter],[offboard]",
             "timeout_min": 10
         },
-        {
-            "model": "iris_dual_gps",
-            "vehicle": "iris_dual_gps",
-            "test_filter": "[multicopter]",
-            "timeout_min": 10
-        },
-        {
-            "model": "iris_opt_flow_mockup",
-            "vehicle": "iris_opt_flow_mockup",
-            "test_filter": "[multicopter][offboard][nogps]",
-            "timeout_min": 10
-        },
         {
             "model": "standard_vtol",
             "vehicle": "standard_vtol",