Change EnvelopeItem dataFactory to FutureOr

[vaind]

Review suggestion for #2417 change envelope-item data factory to FutureOr

Looking at the uses of the data factory, it's almost exclusively synchronous so I think we can change it to FutureOr. Even though this is changing a public API, it shouldn't require any changes by the callers because the type is compatible with Future.

#skip-changelog

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.02%. Comparing base (49cb755) to head (a85b3ed).
Report is 14 commits behind head on enha/performance-improvements.

Additional details and impacted files

@@                      Coverage Diff                       @@
##           enha/performance-improvements    #2444   +/-   ##
==============================================================
  Coverage                          85.01%   85.02%           
==============================================================
  Files                                257      257           
  Lines                               9172     9173    +1     
==============================================================
+ Hits                                7798     7799    +1     
  Misses                              1374     1374           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[denrase]

Looking good. Honestly, I'm not sure if this API is even used, maybe @buenaflor Has some insights?

[buenaflor]

Looking good. Honestly, I'm not sure if this API is even used, maybe @buenaflor Has some insights?

no idea, I doubt that someone uses this api or the number is negligible slim

the change is fine for me