Journey graph with sequential screen views does not link the screen view nodes

# Description

Review the logic for journey graph generation to link sequential screen views. This applies to both iOS and Android.

For example:

``` 
Activity A -> Screen View S1 -> Screen View S2.
```

The current output would like all screen views to the last activity or view controller:

```
A -> S1
A -> S2
```

The expected output is:

```
A -> S1 -> S2
```