Remove initial splits from delta splits generation

[raunaqmorarka]

Description

Minimum split sizes in parquet are determined by parquet writer row group size.
The default parquet row group size is 128MB which makes any initial splits smaller than that unncessary.
Concept of initial splits is intended for formats like TEXT

Additional context and related issues

Release notes

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# Delta Lake
* Catalog configuration properties `delta.max-initial-splits` and `delta.max-initial-split-size` are now defunct and must be removed from cluster configuration properties to successfully start the server. The catalog session property `max_initial_split_size` has been removed. ({issue}`21320`)