[nrf fromtree] tests: drivers: comparator: shell: use platform_allow

Change integration_platform -> platform_allow to not build the
shell test suite for all supported boards.

Upstream PR: zephyrproject-rtos/zephyr#80049

Signed-off-by: Bjarki Arge Andreasen <[email protected]>
(cherry picked from commit 0502189)

Author: bjarki-andreasen

tests/drivers/comparator/shell/testcase.yaml

@@ -3,7 +3,7 @@
 
 tests:
   drivers.comparator.shell:
-    integration_platforms:
+    platform_allow:
       - native_sim
       - native_sim/native/64
     tags: