xmpp: Log server-sent message type='error' as warnings #417

Job	Run time
golangci-lint	32s
test (stable)	1m 55s
test (1.24.x)	1m 47s
build-upload (amd64, windows, windows)	1m 24s
build-upload (amd64, linux, linux)	1m 25s
build-upload (amd64, mac, darwin)	1m 21s
	8m 24s

Provide feedback