refactor: don't use 'out' in IDiscordCache methods

this change is required for async cache (.NET doesn't support async ref/out params)

PluralKit.Bot/Services/EmbedService.cs

@@ -335,10 +335,10 @@ namespace PluralKit.Bot
             var roles = memberInfo?.Roles?.ToList();
             if (roles != null && roles.Count > 0 && showContent)
             {
-                var rolesString = string.Join(", ", roles
-                    .Select(id =>
+                var rolesString = string.Join(", ", (await Task.WhenAll(roles
+                    .Select(async id =>
                     {
-                        _cache.TryGetRole(id, out var role);
+                        var role = await _cache.TryGetRole(id);
                         if (role != null)
                             return role;
                         return new Role()
@@ -346,7 +346,7 @@ namespace PluralKit.Bot
                             Name = "*(unknown role)*",
                             Position = 0,
                         };
-                    })
+                    })))
                     .OrderByDescending(role => role.Position)
                     .Select(role => role.Name));
                 eb.Field(new($"Account roles ({roles.Count})", rolesString.Truncate(1024)));

PluralKit.Bot/Services/LogChannelService.cs

@@ -93,7 +93,7 @@ namespace PluralKit.Bot
         private async Task<Channel?> FindLogChannel(ulong guildId, ulong channelId)
         {
             // TODO: fetch it directly on cache miss?
-            if (await _cache.TryGetChannel(channelId, out var channel))
+            if (await _cache.TryGetChannel(channelId) is Channel channel)
                 return channel;
 
             // Channel doesn't exist or we don't have permission to access it, let's remove it from the database too