[FIX] Introduce AppLivechatBridge.isOnlineAsync method

[renatobecker]

To properly run the AppLivechatBridge.isOnline method, it needs to become an asynchronous method.
Otherwise, we will get an error as shown below when executing it through the Apps-Engine:

W20200204-17:15:09.944(-3)? (STDERR) Exception on find Error: Meteor code must always run within a Fiber. Try wrapping callbacks that you pass to non-Meteor libraries with Meteor.bindEnvironment.
W20200204-17:15:09.945(-3)? (STDERR)     at Object.Meteor._nodeCodeMustBeInFiber (packages/meteor.js:1186:11)
W20200204-17:15:09.945(-3)? (STDERR)     at Meteor.EnvironmentVariable.EVp.get (packages/meteor.js:1199:10)
W20200204-17:15:09.946(-3)? (STDERR)     at Object.collection.<computed> [as find] (packages/matb33_collection-hooks.js:136:37)
W20200204-17:15:09.946(-3)? (STDERR)     at Collection.find (packages/mongo/collection.js:334:29)
W20200204-17:15:09.946(-3)? (STDERR)     at BaseDb.find (app/models/server/models/_BaseDb.js:130:21)
W20200204-17:15:09.946(-3)? (STDERR)     at Users.find (app/models/server/models/_Base.js:116:29)
W20200204-17:15:09.946(-3)? (STDERR)     at Users.findBotAgents (app/models/server/models/Users.js:112:15)
W20200204-17:15:09.946(-3)? (STDERR)     at Object.getBotAgents (app/livechat/server/lib/Livechat.js:96:16)
W20200204-17:15:09.946(-3)? (STDERR)     at Object.online (app/livechat/server/lib/Livechat.js:60:31)
W20200204-17:15:09.947(-3)? (STDERR)     at AppLivechatBridge.isOnline (app/apps/server/bridges/livechat.js:16:19)
W20200204-17:15:09.947(-3)? (STDERR)     at LivechatRead.isOnline (/Volumes/Workspace/Rocket.Chat/node_modules/@rocket.chat/apps-engine/server/accessors/LivechatRead.js:9:36)
W20200204-17:15:09.947(-3)? (STDERR)     at WhatsAppMessageEndpoint.post (evalmachine.<anonymous>:31:56)
W20200204-17:15:09.947(-3)? (STDERR)     at processTicksAndRejections (internal/process/task_queues.js:93:5) { roles: { '$all': [ 'bot', 'livechat-agent' ] } }
``

[d-gubert]

this is a breaking change to the Apps-Engine definition, which blocks us from changing it until the next major version.

@lolimay this is the same problem we've discussed here, can you work with @renatobecker to introduce a new method and deprecate this one?

@rodrigok do you think there is a better way to handle this situation?

[renatobecker]

this is a breaking change to the Apps-Engine definition, which blocks us from changing it until the next major version.

@lolimay this is the same problem we've discussed here, can you work with @renatobecker to introduce a new method and deprecate this one?

@rodrigok do you think there is a better way to handle this situation?

Thanks @d-gubert for your comment, we just need to have a quick definition of this matter because Caixa is waiting for this implementation to be able to use properly their App.
They are complaining about the current behavior on their App because of the current implementation is causing a very bad user experience.

[claassistantio]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ renatobecker
❌ d-gubert
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[rodrigok]

@d-gubert since it was introduced 2 days ago and the release is under release candidate still I don't see any problems incorporating this beaking change.

[rodrigok]

We can release a new version and deprecate the old one where the feature was introduced

[d-gubert]

@rodrigok this functionality has actually been introduced 2 months ago by this PR and has been part of the API since then

[rodrigok]

@d-gubert I see, so, yes, need to create a new method