Fix corner case when there's no container to attach to

[ndeloof]

What I did
Fixed a corner case:
if one run docker compose up --scale helloworld=0 with a single-service compose file, no container is actually created (as expected) and watch will never detect application termination

Related issue
close #8752

(not mandatory) A picture of a cute animal, if possible in relation to what you did

[codecov]

Codecov Report

Base: 77.02% // Head: 77.02% // No change to project coverage 👍

Coverage data is based on head (d3d30cf) compared to base (0234e13).
Patch has no changes to coverable lines.

Additional details and impacted files

@@           Coverage Diff           @@
##               v2   #10058   +/-   ##
=======================================
  Coverage   77.02%   77.02%           
=======================================
  Files           2        2           
  Lines         235      235           
=======================================
  Hits          181      181           
  Misses         48       48           
  Partials        6        6           

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[milas]

Looks good - does this actually address the linked issue, however?

AFAICT that issue isn't about "no container to attach to" cases but <svc>=0 being a way to exclude a service from launching as part of up without having to list out every other service

[ndeloof]

#8752 indeeds report another issue, but the latest codebase doesn't behaves as reported (scale=0 is well supported now), still the reported scenario demonstrates as a deadlock when scale=0 is set (aka "regression").