[ClassificationDataset Manager] Absolute Sampling not working

[Fabian Thiel]

When switching from Relative to *Absolute* under Sample size, the text entry field still shows the “%” label and value is not applied after clicking Set

I would assume if I want to sample 5 of every class, I change to Absolute, enter 5, click Set and the Sample size column is auto filled with 5 (or max if n samples < 5).

[Andreas Rabe]

https://github.com/EnMAP-Box/enmap-box/commit/509c4c702aa128377e0719cca7fb787b8fac8b21