chan_sip: Fix output of 'sip set debug off'.

When sip.conf contains 'sipdebug=yes' it is impossible to disable it
using CLI 'sip set debug off'.  This corrects the output of that CLI
command to instruct the user to turn sipdebug off in the configuration
file.

ASTERISK-23462 #close

Change-Id: I1cceade9caa9578e1b060feb832e3495ef5ad318

channels/chan_sip.c

@@ -22574,7 +22574,12 @@ static char *sip_do_debug(struct ast_cli_entry *e, int cmd, struct ast_cli_args
 		} else if (!strcasecmp(what, "off")) {
 			sipdebug &= ~sip_debug_console;
 			sipdebug_text = 0;
-			ast_cli(a->fd, "SIP Debugging Disabled\n");
+			if (sipdebug == sip_debug_none) {
+				ast_cli(a->fd, "SIP Debugging Disabled\n");
+			} else {
+				ast_cli(a->fd, "SIP Debugging still enabled due to configuration.\n");
+				ast_cli(a->fd, "Set sipdebug=no in sip.conf and reload to actually disable.\n");
+			}
 			return CLI_SUCCESS;
 		}
 	} else if (a->argc == e->args + 1) { /* ip/peer */