Previously, if the filter chain threw an unhandled exception,
WebRequestTraceFilter would record a trace with a response status of
200. This occurred because response.getStatus() would return 200 as
the container had not yet caught the exception and mapped it to an
error response.

This commit updates WebRequestTraceFilter to align its behaviour with
MetricsFilter. It now assumes that the response status will be a 500
and only updates that to the status of the response if the call to the
filter chain returns successfully.

To avoid making a breaking change to the signature of the protected
enhanceTrace method, an HttpServletResponseWrapper is used to include
the correct status in the trace.

Closes gh-5331