tests/subsys/logging/log_switch_format: fix incomplete logs

log_Switch_format test has incomplete handler logs on frdm_k64f
and also a false positive for logging.log_switch_format.immediate
testcase due to harness console which does not wait for
completion of ztest testcases to indicate pass/fail status to twister.

Fixes #46368

Signed-off-by: Aastha Grover <aastha.grover@intel.com>