[Bug - task_ivar_variant_call] Fix potential places for failure

[Michal-Babins]

🐛

📝 Describe the Issue

Ivar variant call is failing when VARIANT_NUM variable is not found, this is do to addition of set -euo pipefail. Here is what is happening

• The ivar pipeline found no variants (output shows "SNP: 0")
• The grep "TRUE" command found no matches and failed due to set -euo pipefail
• This prevents execution of subsequent commands that would create VARIANT_NUM

When no variants are found, grep exits with code 1, causing the entire script to fail before it can write "0" to VARIANT_NUM. This makes the file missing for delocalization VARIANT_NUM.

🔁 How to Reproduce

Run on terra

💻 Version Information

PhB V.2.3.0