LineChartData(dataSets:) doesn't always plot all points

The change for issue #4577 and possibly the changes leading up to it caused LineChartData(dataSets:) to stop plotting all data points, if the LineChartDataSet entries are not all the same size. Only the first point is plotted for the shorter data set. To reproduce, run this code:
```swift
let chart = LineChartView()
chart.data = LineChartData(
dataSets: [
LineChartDataSet(entries: [
ChartDataEntry(x: 0, y: 0),
ChartDataEntry(x: 10, y: 10),
ChartDataEntry(x: 20, y: 20)
]),
LineChartDataSet(entries: [
ChartDataEntry(x: 0, y: 5),
ChartDataEntry(x: 10, y: 15) // this point is not plotted using commit 931ebe8
])
]
)
```
When I reverted back to the earlier commit 857db24 this code plots all five data points.

_Originally posted by @InvaderZim62 in https://github.com/danielgindi/Charts/issues/4577#issuecomment-790079474_