Override `split_rows` in `TaggedTable` to return two `TaggedTable`s

[lars-reimann]

Is your feature request related to a problem?

split_rows in TaggedTable returns two Tables.

Desired solution

Override it to return two TaggedTables instead.

Possible alternatives (optional)

No response

Screenshots (optional)

No response

Additional Context (optional)

No response

[lars-reimann]

Deferred until #647 is discussed. This might not be needed anymore.

[lars-reimann]

Implementing #647 instead.