acceptance: remove obsolete presets_name_prefix_vs_index_endpoint test

The test was a Badness fixture capturing the gap where a literal
endpoint_name on a VS index would not follow the endpoint's name
prefix. Now that neither VS endpoints (#5209) nor VS indexes are
prefixed, the literal form correctly points at the (unprefixed)
endpoint, and all three branches of the fixture produce identical
output.

Co-authored-by: Isaac

Author: janniklasrose