[misc] OError.tag all the errors in async contexts

See the docs of OError.tag:
https://github.com/overleaf/o-error#long-stack-traces-with-oerrortag
(currently at 221dd902e7bfa0ee92de1ea5a3cbf3152c3ceeb4)

I am tagging all errors at each async hop. Most of the controller code
 will only ever see already tagged errors -- or new errors created in
 our app code. They should have enough info that we do not need to tag
 them again.

services/real-time/test/unit/js/WebsocketControllerTests.js

@@ -1464,8 +1464,8 @@ describe('WebsocketController', function () {
         return this.client.disconnect.called.should.equal(true)
       })
 
-      it('should log an error', function () {
-        return this.logger.error.called.should.equal(true)
+      it('should not log an error', function () {
+        return this.logger.error.called.should.equal(false)
       })
 
       return it('should call the callback with the error', function () {