Update default VCF ingestion batch size to 100

[gspowley]

Update the default VCF ingestion batch size to 100 and reduce the VCF header memory usage estimate based on example ingestion profiles.

These numbers are used to estimate the amount of memory needed per UDF node. The actual memory usage will be data dependent.

UDF node memory resources can be set with the ingest_resources arg of tiledb.cloud.vcf.ingest to optimize the memory resources for dataset with known memory requirements.

For example:

ingest_resources = {
    "cpu": "8",
    "memory": "32Gi",
}

[shortcut-integration]

This pull request has been linked to Shortcut Story #33723: Update default VCF batch size to 100.