Converting str to float fallbacks to original value in case of exception

[czajkub]

The issue lies with converting the value field's values to float, despite some of them containing strings or integers. String values will be now reverted to their original state after causing a ValueError during casting, while pure integer values will still be casted into their float equivalent - which doesn't seem to pose any issues

[KaliszS]

Thanks and welcome to the contributors’ crew! I have just modified the title of the PR, because it’s better to have a short description of what was changed there. The issue reference will be added to the squashed commit (we use the squash and merge option, so merging to the main branch will create one commit containing all changes from the PR, there we can set a new commit message).

And just to note why it was solved like that before, in case some visitors are curious: Elasticsearch requires strict numeric values to include data rows in the analysis, which we were using to verify results from Claude Desktop. Unfortunately, we missed the fact that values in the dataset might also be non-numeric.