Set correct CompletePromise response code

[dfarr]

for a timer promise: 403
for a regular promise: 403 if strict, otherwise 200

Fixes: #370
Fixes: #371
Fixes: #372
Fixes: #373

[codecov]

Codecov Report

Attention: Patch coverage is 37.50000% with 5 lines in your changes missing coverage. Please review.

Project coverage is 55.86%. Comparing base (1218336) to head (5a7be38).

Files	Patch %	Lines
internal/app/coroutines/completePromise.go	37.50%	2 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #374      +/-   ##
==========================================
- Coverage   55.88%   55.86%   -0.03%     
==========================================
  Files         124      124              
  Lines       10596    10601       +5     
==========================================
  Hits         5922     5922              
- Misses       4199     4201       +2     
- Partials      475      478       +3     

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[dfarr]

The following DST runs are passing with the same seeds:

• https://github.com/resonatehq/resonate/actions/runs/10120673603
• https://github.com/resonatehq/resonate/actions/runs/10120673275