Fix "files is not defined" error in S3 object picker

[mbklein]

Summary

Fix intermittent "files is not defined" error in S3 object picker

Specific Changes in this PR

• add conditional chain operator to handleFileAction
• add conditional chain operator to findFileSetByUri

Version bump required by the PR

See Semantic Versioning 2.0.0 for help discerning which is required.

• Patch
• Minor
• Major

Steps to Test

1. Browse to a work and open the browser's developer tools to the console tab.
2. Click Add A Fileset
3. Navigate around the file picker and make sure there are no errors reported in the console.

🚀 Deployment Notes

Note - if you check any of these boxes go to the (always open) main <- staging PR and add detailed notes and instructions to help out others who may end up deploying your changes to production

• Backward compatible API changes
  • Database Schema changes
  • GraphQL API
  • Elasticsearch API
  • Ingest Sheet
  • CSV metadata export/update API
  • Shared Links export API
• Backwards-incompatible API changes
  • Database Schema changes
  • GraphQL API
  • Elasticsearch API
  • Ingest Sheet
  • CSV metadata export/update API
  • Shared Links export API
• Requires data migration
• Requires database triggers disabled during deployment/migration
• Requires reindex
• Terraform changes
  • Adds/requires new or changed Terraform variables
• Pipeline configuration changes (requires mix meadow.pipeline.setup run)
• Requires new variable added to miscellany
• Specific deployment synchronization instructions with other apps/API's
• Other specific instructions/tasks

Tested/Verified

• End users/stakeholders

[bmquinn]

Looks great! 👍