static-test: `cppcheck` sub-test raises error

[luisan00]

Description

The static-tests workflow raises:

./dist/tools/cppcheck/check.sh x
  Command output:
  
  	wifi-subsys/components/uart/src/at_handler.c:108: warning (nullPointer): Possible null pointer dereference: key_value
  	wifi-subsys/components/uart/src/at_handler.c:53: style (constParameter): Parameter 'command' can be declared with const
  
  Warning: Possible null pointer dereference: key_value
  
  If you are sure this is a false positive, you can suppress this by adding the following comment above this line:
  
      /* cppcheck-suppress nullPointer
       * (reason: <your reason why you think this is a false positive>) */
  
Warning: Parameter 'command' can be declared with const

If you are sure this is a false positive, you can suppress this by adding the following comment above this line:

    /* cppcheck-suppress constParameter
     * (reason: <your reason why you think this is a false positive>) */

Steps to reproduce the issue

Expected results

no errors

Actual results

errors

Versions

It is not related to any concrete version