samples: tests: Exclude nRF54L15 NS for unsupported tests/samples

The ADC and watchdog samples are not currently supported for the
non secure target of the nRF54L15 DK.

Add exclusions for these until they are supported.

Signed-off-by: Georgios Vasilakis <georgios.vasilakis@nordicsemi.no>

samples/drivers/watchdog/sample.yaml

@@ -25,6 +25,7 @@ tests:
       - panb511evb/nrf54l15/cpuapp
       - panb511evb/nrf54l15/cpuflpr
       - panb511evb/nrf54l15/cpuflpr/xip
+      - nrf54l15dk/nrf54l15/cpuapp/ns
   sample.drivers.watchdog.stm32_wwdg:
     extra_args: DTC_OVERLAY_FILE=boards/stm32_wwdg.overlay
     filter: dt_compat_enabled("st,stm32-window-watchdog")

tests/drivers/adc/adc_api/testcase.yaml

@@ -10,6 +10,7 @@ tests:
     platform_exclude:
       - nucleo_u031r8
       - panb511evb/nrf54l15/cpuapp
+      - nrf54l15dk/nrf54l15/cpuapp/ns
   drivers.adc.b_u585i_iot02a_adc4:
     extra_args:
       - DTC_OVERLAY_FILE="boards/b_u585i_iot02a_adc4.overlay"

tests/drivers/watchdog/wdt_basic_api/testcase.yaml

@@ -24,6 +24,7 @@ tests:
       - panb511evb/nrf54l15/cpuflpr
       - panb511evb/nrf54l15/cpuflpr/xip
       - mimxrt700_evk/mimxrt798s/cm33_cpu1
+      - nrf54l15dk/nrf54l15/cpuapp/ns
   drivers.watchdog.stm32wwdg:
     filter: dt_compat_enabled("st,stm32-window-watchdog") or dt_compat_enabled("st,stm32-watchdog")
     extra_args: DTC_OVERLAY_FILE="boards/stm32_wwdg.overlay"