Cypress/fix test version slicing and skipping download binary test

[mmartin24]

Issue

The regression test regarding download binaries failed when downloading -rc: https://github.com/epinio/epinio-end-to-end-tests/actions/runs/6141788148/job/16664323997#step:14:61

Done

• Changing assertion from eq to contain to prevent hard breaking when using -rc versions
• Skipping download binaries test either until release or until we consider -rc binaries downloadable
• Expanding slicing characters from 6 to 7 given than now we are starting to use versions > v1.9.0

Tests passing:

• https://github.com/epinio/epinio-end-to-end-tests/actions/runs/6143506679/job/16667088938
• https://github.com/epinio/epinio-end-to-end-tests/actions/runs/6143458353/job/16667231977#step:3:74