Remove nfcore_external_java_deps.jar from lib directory in pipeline template

[drpatelh]

This is no longer required as it should have been replaced by the nf-validation plugin.

[drpatelh]

Tests are failing due to:

╭─ [✗] 2 Pipeline Tests Failed ────────────────────────────────────────────────╮
│                                                                              │
│ files_exist: File not found: lib/nfcore_external_java_deps.jar               │
│ files_unchanged: File does not exist: lib/nfcore_external_java_deps.jar      │
│                                                                              │
╰──────────────────────────────────────────────────────────────────────────────╯

Do we generate a lint error in the future if this file is found in the template or we keep it there for those to remove if they are using nf-validation?

[mirpedrol]

LGTM!