MOD-5211: Propagate errors from shards to coordinator

[raz-mon]

Currently, the coordinator neglects errors it gets from the shards. This PR fixes this behavior, such that the coordinator will report to the user any error the shards send it.

• Note: These are not timeout errors, which are taken care of separately here.

Mark if applicable

• This PR introduces API changes
• This PR introduces serialization changes

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (b7bdc96) 82.82% compared to head (2c60b5f) 82.80%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3938      +/-   ##
==========================================
- Coverage   82.82%   82.80%   -0.02%     
==========================================
  Files         192      192              
  Lines       32650    32658       +8     
==========================================
+ Hits        27041    27043       +2     
- Misses       5609     5615       +6     

Files	Coverage Δ
src/aggregate/aggregate_exec.c	95.76% <ø> (+0.83%)	⬆️
src/aggregate/aggregate_request.c	97.54% <ø> (ø)
src/reply.c	83.51% <ø> (-0.06%)	⬇️
coord/src/dist_aggregate.c	90.93% <88.88%> (-0.85%)	⬇️

... and 2 files with indirect coverage changes

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[GuyAv46]

Nicely done!
Few comments

[github-actions]

Successfully created backport PR for 2.8:

• [2.8] MOD-5211: Propagate errors from shards to coordinator #3962

[github-actions]

Backport failed for 2.10, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally.

git fetch origin 2.10
git worktree add -d .worktree/backport-3938-to-2.10 origin/2.10
cd .worktree/backport-3938-to-2.10
git checkout -b backport-3938-to-2.10
ancref=$(git merge-base b7bdc96723d862060dee771602f99e22c82b8043 2c60b5fa53745073730165379fcb71a7f254fbc9)
git cherry-pick -x $ancref..2c60b5fa53745073730165379fcb71a7f254fbc9

[github-actions]

Backport failed for 2.6, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally.

git fetch origin 2.6
git worktree add -d .worktree/backport-3938-to-2.6 origin/2.6
cd .worktree/backport-3938-to-2.6
git checkout -b backport-3938-to-2.6
ancref=$(git merge-base b7bdc96723d862060dee771602f99e22c82b8043 2c60b5fa53745073730165379fcb71a7f254fbc9)
git cherry-pick -x $ancref..2c60b5fa53745073730165379fcb71a7f254fbc9