Set durable annotation for AMQP messages

This is similar to #11057

What?
For incoming AMQP messages, always set the durable message container annotation.

Why?
Even though defaulting to durable=true when no durable annotation is set, as prior
to this commit, is good enough, explicitly setting the durable annotation makes
the code a bit more future proof and maintainable going forward in 4.0 where we
will rely more on the durable annotation because AMQP 1.0 message headers will
be omitted in classic and quorum queues.

The performance impact of always setting the durable annotation is negligible.

deps/rabbit/src/mc_amqp.erl

@@ -17,9 +17,7 @@
         ]).
 
 -import(rabbit_misc,
-        [maps_put_truthy/3,
-         maps_put_falsy/3
-        ]).
+        [maps_put_truthy/3]).
 
 -type message_section() ::
     #'v1_0.header'{} |
@@ -185,8 +183,6 @@ get_property(durable, Msg) ->
         #msg_body_encoded{header = #'v1_0.header'{durable = Durable}}
           when is_boolean(Durable) ->
             Durable;
-        #msg_body_encoded{header = #'v1_0.header'{durable = {boolean, Durable}}} ->
-            Durable;
         _ ->
             %% fallback in case the source protocol was old AMQP 0.9.1
             case message_annotation(<<"x-basic-delivery-mode">>, Msg, undefined) of
@@ -644,17 +640,16 @@ essential_properties(#msg_body_encoded{message_annotations = MA} = Msg) ->
                  _ ->
                      undefined
              end,
-    Anns = maps_put_falsy(
-             ?ANN_DURABLE, Durable,
+    Anns0 = #{?ANN_DURABLE => Durable},
+    Anns = maps_put_truthy(
+             ?ANN_PRIORITY, Priority,
              maps_put_truthy(
-               ?ANN_PRIORITY, Priority,
+               ?ANN_TIMESTAMP, Timestamp,
                maps_put_truthy(
-                 ?ANN_TIMESTAMP, Timestamp,
+                 ttl, Ttl,
                  maps_put_truthy(
-                   ttl, Ttl,
-                   maps_put_truthy(
-                     deaths, Deaths,
-                     #{}))))),
+                   deaths, Deaths,
+                   Anns0)))),
     case MA of
         [] ->
             Anns;