tests: drivers: uart: Remove nrf53 from allowed platform

nrf5340dk setup does not support this feature properly.
Interrupt driven API is not recommended way of using UART
escpacially in time sensitive case like this one.

Signed-off-by: Bartosz Miller <[email protected]>

Author: nordic-bami

tests/drivers/uart/uart_passtrough/testcase.yaml

@@ -9,10 +9,8 @@ common:
   harness_config:
     pytest_dut_scope: session
   platform_allow:
-    - nrf5340dk/nrf5340/cpuapp
     - nrf54h20dk/nrf54h20/cpuapp
   integration_platforms:
-    - nrf5340dk/nrf5340/cpuapp
     - nrf54h20dk/nrf54h20/cpuapp
 
 tests: