Close flags precomputed assignments body for unsuccessful response

[0xnm]

What does this PR do?

Just a small improvement to close Flags response body on the unsuccessful response as well.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 71.41%. Comparing base (61409f2) to head (332a8d4).

Files with missing lines	Patch %	Lines
...s/internal/net/PrecomputedAssignmentsDownloader.kt	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3280      +/-   ##
===========================================
- Coverage    71.68%   71.41%   -0.28%     
===========================================
  Files          942      942              
  Lines        34811    34812       +1     
  Branches      5899     5900       +1     
===========================================
- Hits         24954    24858      -96     
- Misses        8233     8294      +61     
- Partials      1624     1660      +36     

Files with missing lines	Coverage Δ
...s/internal/net/PrecomputedAssignmentsDownloader.kt	96.55% <0.00%> (-3.45%)	⬇️

... and 38 files with indirect coverage changes

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