PD-2905: Remove/update MergeStarOutput task

[aawdeh]

Checklist

If you can answer "yes" to the following items, please add a checkmark next to the appropriate checklist item(s) and notify our WARP team by tagging @broadinstitute/warp-admins in a comment on this PR.

• Did you add inputs, outputs, or tasks to a workflow?
• Did you modify, delete or move: file paths, file names, input names, output names, or task names?
• If you made a changelog update, did you update the pipeline version number?

[github-actions]

Remember to squash merge!

[github-actions]

🔍Changelog Validation Results:

Comparing changelogs for pipelines that differ from the versions on 'origin/develop':
All changelog files are valid for this release.

[github-actions]

Remember to squash merge!

[github-actions]

🔍Version Validation Results:

Comparing versions and changelogs for pipelines that differ from the versions on 'origin/staging':
All WDLs and changelog files appear to be valid for this release.

[github-actions]

🔍Version Validation Results:

Comparing versions and changelogs for pipelines that differ from the versions on 'origin/staging':
All WDLs and changelog files appear to be valid for this release.

[github-actions]

🔍Changelog Validation Results:

Comparing changelogs for pipelines that differ from the versions on 'origin/develop':
All changelog files are valid for this release.

[github-actions]

Remember to squash merge!

[github-actions]

🔍Version Validation Results:

Comparing versions and changelogs for pipelines that differ from the versions on 'origin/staging':
All WDLs and changelog files appear to be valid for this release.

[github-actions]

🔍Changelog Validation Results:

Comparing changelogs for pipelines that differ from the versions on 'origin/develop':
All changelog files are valid for this release.

[github-actions]

Remember to squash merge!

[github-actions]

🔍Version Validation Results:

Comparing versions and changelogs for pipelines that differ from the versions on 'origin/staging':
All WDLs and changelog files appear to be valid for this release.

[github-actions]

🔍Changelog Validation Results:

Comparing changelogs for pipelines that differ from the versions on 'origin/develop':
All changelog files are valid for this release.