Dashboard charts do not display data if multiple packet types are used

[ghost]

Describe the bug
If one uses a parser that identifies via a header multiple packet types with different fields, the charts can't handle this.

To Reproduce
Create e.g. a sigfox packet where the first byte is interpreted as packet type.
Depending on this packet type create different keys.
The keys will show up in table, but a line chart will no longer load.

Temporary workaround
Always update all keys, even if the keys that are not used inside this "packet type", simply set them e.g. to 0.

Expected behavior
Data chart should only try to display data for Sigfox packets where the keys exist if the keys are displayed inside the chart.