Improve exit code for message sending

Exit with 0 status code if the message was sent successfully to at least
one recipient, otherwise exit with status code 2 or 4 (for untrusted).

Fixes #828

graalvm-config-dir/reflect-config.json

@@ -300,6 +300,10 @@
   "allDeclaredMethods":true,
   "allDeclaredClasses":true}
 ,
+{
+  "name":"org.asamk.Signal$Error$UntrustedIdentity",
+  "methods":[{"name":"<init>","parameterTypes":["java.lang.String"] }]}
+,
 {
   "name":"org.asamk.Signal$Group",
   "allDeclaredMethods":true,
@@ -458,9 +462,7 @@
   "allDeclaredFields":true,
   "queryAllDeclaredMethods":true,
   "queryAllDeclaredConstructors":true,
-  "methods":[
-    {"name":"id","parameterTypes":[] }
-  ]}
+  "methods":[{"name":"id","parameterTypes":[] }]}
 ,
 {
   "name":"org.asamk.signal.json.JsonCallMessage$Hangup",