sharkd: Increase JSON buffer size from 2048 to 8192 bytes

This commit increases the maximum size for the JSON commands processed
by `sharkd` from 2048 to 8192 bytes.  The primary reason for this
change is to allow larger filters in `filter0`...`filter9` arguments
which, combined with the outer JSON boilerplate, can cause a command
to quickly hit the existing 2048-byte limit.

sharkd_session.c

@@ -5837,7 +5837,7 @@ sharkd_session_process(char *buf, const jsmntok_t *tokens, int count)
 int
 sharkd_session_main(int mode_setting)
 {
-    char buf[2 * 1024];
+    char buf[8 * 1024];
     jsmntok_t *tokens = NULL;
     int tokens_max = -1;