chore(code): Early check for sync actor presence

[ancazamfir]

Closes: #XXX
Bits from initial work on #771

---

PR author checklist

For all contributors

• Reference GitHub issue
• Ensure PR title follows the conventional commits spec

For external contributors

• Maintainers of Malachite are allowed to push changes to the branch

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.79%. Comparing base (b17d82c) to head (130e9b4).
Report is 1 commits behind head on main.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #822      +/-   ##
==========================================
- Coverage   75.81%   75.79%   -0.02%     
==========================================
  Files         169      169              
  Lines       14682    14682              
==========================================
- Hits        11130    11127       -3     
- Misses       3552     3555       +3     

Flag	Coverage Δ
integration	75.48% <ø> (-0.02%)	⬇️
mbt	20.63% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
core	∅ <ø> (∅)
engine	∅ <ø> (∅)
app	∅ <ø> (∅)
starknet	∅ <ø> (∅)