correctly determine the vis instance in all cases

[foxriver76]

• This fixes e.g. the problem that a project called 3_Test will lead to the case, that adapter-react-v5 will determine the instance as 3, because of https://github.com/ioBroker/adapter-react-v5/blob/bae98e05d9d0df4443b59bda6b7ac08f3135bf4f/src/GenericApp.js#L139 is using the first char in window.location.search if it is a number, because vis-2 url is build like http://localhost:8082/vis-2/?3test#default but does not contain instance= in url
• While vis-2 is a singleton adapter, someone could add the single instance as a different than 0, this is edgy but also caught here, else it would be enough to just pass 0. Instead the backend is injecting the real instance number into the window object leading to an accurate instance detection
• closes Control Datapoints not working properly and no Data about Batterystatus #331