samples, tests: convert string-based twister lists to YAML lists

Twister now supports using YAML lists for all fields that were written
as space-separated lists. Used twister_to_list.py script. Some artifacts
on string length are due to how ruamel dumps content.

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>

samples/boards/stm32/power_mgmt/blinky/sample.yaml

@@ -2,7 +2,9 @@ sample:
   name: STM32 GPIO Power Management
 tests:
   sample.boards.stm32.power_mgmt.blinky:
-    tags: LED power
+    tags:
+      - LED
+      - power
     harness: console
     harness_config:
       type: one_line

samples/boards/stm32/power_mgmt/serial_wakeup/sample.yaml

@@ -2,7 +2,11 @@ sample:
   name: STM32 Power Management Serial Wakeup
 tests:
   sample.boards.stm32.power_mgmt.serial_wakeup:
-    tags: UART Wake up power
+    tags:
+      - UART
+      - Wake
+      - up
+      - power
     harness: console
     harness_config:
       type: multi_line

samples/boards/stm32/power_mgmt/standby_shutdown/sample.yaml

@@ -2,8 +2,12 @@ sample:
   name: STM32 GPIO Power Management
 tests:
   sample.boards.stm32.power_mgmt.standby_shutdown:
-    platform_allow: nucleo_l476rg disco_l475_iot1
-    tags: LED power
+    platform_allow:
+      - nucleo_l476rg
+      - disco_l475_iot1
+    tags:
+      - LED
+      - power
     harness: console
     harness_config:
       type: multi_line
@@ -13,7 +17,6 @@ tests:
         - "Press and hold the user button:"
         - "when LED2 is OFF to enter to Shutdown Mode"
         - "when LED2 is ON to enter to Standby Mode"
-    filter: dt_compat_enabled("zephyr,power-state") and
-            dt_enabled_alias_with_parent_compat("led0", "gpio-leds") and
-            dt_compat_enabled("st,stm32-lptim")
+    filter: dt_compat_enabled("zephyr,power-state") and dt_enabled_alias_with_parent_compat("led0",
+      "gpio-leds") and dt_compat_enabled("st,stm32-lptim")
     extra_args: "CONFIG_DEBUG=y"

samples/boards/stm32/power_mgmt/stm32wb_ble/sample.yaml

@@ -4,4 +4,6 @@ tests:
   sample.boards.stm32.pm.stm32wb_ble_pm:
     harness: bluetooth
     platform_allow: nucleo_wb55rg
-    tags: bluetooth pm
+    tags:
+      - bluetooth
+      - pm