Fix MAM cache name

When mod_mam_cache_user checks its cache, it gives its own module name
to mongoose_user_cache so that this one fetches the config to see if it
has configured its own cache or is reusing some other module's cache.
The problem is that mongoose_user_cache will check for the module key,
but it the current implementation, we are hiding it behind a cache key
to contain the cache config.

So by just moving the config a level up, mongoose_user_cache can find it.

src/mam/mod_mam_cache_user.erl

@@ -29,8 +29,8 @@
 %%====================================================================
 
 -spec start(mongooseim:host_type(), gen_mod:module_opts()) -> ok.
-start(HostType, Opts = #{cache := CacheOpts}) ->
-    start_cache(HostType, CacheOpts),
+start(HostType, Opts) ->
+    start_cache(HostType, Opts),
     ejabberd_hooks:add(hooks(HostType, Opts)),
     ok.
 

src/mam/mod_mam_meta.erl

@@ -244,7 +244,7 @@ add_rdbms_deps(user_cache, Type, #{cache_users := true, cache := CacheOpts}, Dep
                 internal -> Deps;
                 mod_cache_users -> add_dep(mod_cache_users, Deps)
             end,
-    add_dep(mod_mam_cache_user, #{Type => true, cache => CacheOpts}, Deps1);
+    add_dep(mod_mam_cache_user, CacheOpts#{Type => true}, Deps1);
 add_rdbms_deps(async_writer, Type, #{async_writer := AsyncOpts = #{enabled := true}}, Deps) ->
     Deps1 = add_dep(rdbms_arch_module(Type), #{no_writer => true}, Deps),
     add_dep(rdbms_async_arch_module(Type), AsyncOpts, Deps1);