[OpenLineage] Fix datasets in GCSTimeSpanFileTransformOperator

[kacpermuda]

Currently we are including all files as datasets which can lead to increasing the size of the event and make matching datasets between jobs harder.

With that change, we are using prefixes from the user as dataset names and not full file paths. This way, user can easily control the size of the event and also ensure proper matching, when the same two prefixes are passed to different operators. I am also removing the list of files that was saved for the purpose of lineage datasets, introduced in #35838 .

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