Fix `UxDataset.integrate()` to work for multiple data arrays in the dataset

[erogluorhan]

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Describe the feature you'd like added to this project

This method currently works only if there is a single data array in the dataset.

A deprecation warning has started to be shown after PR #460. In the November release (v2023.11.0), replace it with a version that can work with multiple data arrays in a dataset.

Describe the solution you'd like For integration of multiple data arrays in the dataset, use the UxDataArray.integrate() method for each of them and return a new dataset with the integrated values.