res_pjsip: Add headers to AMI Event ContactStatusDetail

* Added Useragent and RegExpire headers to AMI Event
ContactStatusDetail with associated documentation.

ASTERISK-25903 #close

Change-Id: If3d121e943e588d016ba51d4eb9c6a421a562239

res/res_pjsip.c

@@ -1829,6 +1829,12 @@
 				<parameter name="EndpointName">
 					<para>The name of the endpoint associated with this information.</para>
 				</parameter>
+				<parameter name="UserAgent">
+					<para>Content of the User-Agent header in REGISTER request</para>
+				</parameter>
+				<parameter name="RegExpire">
+					<para>Absolute time that this contact is no longer valid after</para>
+				</parameter>
 			</syntax>
 		</managerEventInstance>
 	</managerEvent>

res/res_pjsip/pjsip_options.c

@@ -1130,6 +1130,8 @@ static int format_contact_status(void *obj, void *arg, int flags)
 
 	ast_str_append(&buf, 0, "AOR: %s\r\n", wrapper->aor_id);
 	ast_str_append(&buf, 0, "URI: %s\r\n", contact->uri);
+	ast_str_append(&buf, 0, "UserAgent: %s\r\n", contact->user_agent);
+	ast_str_append(&buf, 0, "RegExpire: %ld\r\n", contact->expiration_time.tv_sec);
 	ast_str_append(&buf, 0, "Status: %s\r\n", ast_sip_get_contact_status_label(status->status));
 	if (status->status == UNKNOWN) {
 		ast_str_append(&buf, 0, "RoundtripUsec: N/A\r\n");