examples/nimble: fix setting DUT class in example tests

Pass dut_class=ESP32DUT in the examples where this was missing.

examples/bluetooth/nimble/blehr/blehr_test.py

@@ -129,7 +129,7 @@ def test_example_app_ble_hr(env, extra_data):
     subprocess.check_output(['hciconfig','hci0','reset'])
 
     # Acquire DUT
-    dut = env.get_dut("blehr", "examples/bluetooth/nimble/blehr")
+    dut = env.get_dut("blehr", "examples/bluetooth/nimble/blehr", dut_class=ESP32DUT)
 
     # Get binary file
     binary_file = os.path.join(dut.app.binary_path, "blehr.bin")

examples/bluetooth/nimble/bleprph/bleprph_test.py

@@ -150,7 +150,7 @@ def test_example_app_ble_peripheral(env, extra_data):
     subprocess.check_output(['hciconfig','hci0','reset'])
 
     # Acquire DUT
-    dut = env.get_dut("bleprph", "examples/bluetooth/nimble/bleprph")
+    dut = env.get_dut("bleprph", "examples/bluetooth/nimble/bleprph", dut_class=ESP32DUT)
 
     # Get binary file
     binary_file = os.path.join(dut.app.binary_path, "bleprph.bin")