Remove redundant check

jm.ID is already checked in the outer "if",
so theres no reason to check it again here.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

pkg/jsonmessage/jsonmessage.go

@@ -183,7 +183,7 @@ func DisplayJSONMessagesStream(in io.Reader, out io.Writer, terminalFd uintptr,
 			} else {
 				diff = len(ids) - line
 			}
-			if jm.ID != "" && isTerminal {
+			if isTerminal {
 				// NOTE: this appears to be necessary even if
 				// diff == 0.
 				// <ESC>[{diff}A = move cursor up diff rows