fix(s3stream): prevent commit object 0 when compacting single object

[SCNieh]

No description provided.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 55.94%. Comparing base (336fe9e) to head (19fce90).
Report is 2 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #953      +/-   ##
============================================
+ Coverage     55.90%   55.94%   +0.03%     
- Complexity     1264     1267       +3     
============================================
  Files           133      133              
  Lines          8534     8534              
  Branches        789      789              
============================================
+ Hits           4771     4774       +3     
  Misses         3327     3327              
+ Partials        436      433       -3     

Components	Coverage Δ
RocketMQ Broker	∅ <ø> (∅)
RocketMQ Common	5.80% <ø> (ø)
RocketMQ Controller	57.39% <ø> (ø)
RocketMQ Proxy	37.28% <ø> (+0.10%)	⬆️
RocketMQ Store	73.65% <ø> (+0.04%)	⬆️
RocketMQ Stream	∅ <ø> (∅)
RocketMQ Metadata	35.44% <ø> (ø)

see 2 files with indirect coverage changes