MT#55283 fix sdes_accept logic booboo

Using `l->next` as a test for whether only one element is left in the
list is not reliable. Use the actual list length instead.

Update one affected test.

Closes #1961

Change-Id: I5773715700220cd762e61090bac941ddd33afd9b
(cherry picked from commit 02897ccb46)

daemon/call.c

@@ -1957,10 +1957,8 @@ static void __sdes_accept(struct call_media *media, const sdp_ng_flags *flags) {
 			/* stop the iteration intentionally, if only one suite is left
 			 * this helps with a case, when the offerer left with no suites,
 			 * which can be allowed, but we need to still have at least something */
-			if (l->next == NULL) {
-				l = l->prev;
+			if (media->sdes_in.length == 1)
 				break;
-			}
 
 			ilogs(crypto, LOG_DEBUG, "Dropping offered crypto suite '%s' from offer due to %s",
 				offered_cps->params.crypto_suite->name,

t/auto-daemon-tests-sdes-manipulations.pl

@@ -1418,7 +1418,7 @@ c=IN IP4 203.0.113.1
 a=rtpmap:0 PCMU/8000
 a=sendrecv
 a=rtcp:PORT
-a=crypto:4 AES_256_CM_HMAC_SHA1_32 inline:CRYPTO256
+a=crypto:3 AES_256_CM_HMAC_SHA1_80 inline:CRYPTO256
 SDP