LPS-48158 we need stacktrace at JSON WS at debug level

Hi Igor,

Your yesterday commit in order to avoid generate a lot of output at liferay log was fine, but I think it is necessary to add the stacktrace at least at debug level:
  - Normal function of JSON will be to trace only one line with the problem (as commited at master)I
  - But, in case of a problem at a customer, the customer will open a ticket to us (liferay support) and we will need more information about the problem.
  - With this pull-request we will be able to temporary ask to customer to activate the "debug" level. commit: https://github.com/jorgediaz-lr/liferay-portal/commit/3ee7dbb8e079b29e45517e18c1c637892e040006

For my problem with Liferay Sync (SYNC-1247) there is no traces at "sync-web" plugin, so more tracing at JSONWebServiceServiceAction at debug level is necessary.

Thank you