fix: process ws return route messages serially

[TimoGlastra]

We were already processing messages serially for pickup v1 and v2. This pr updates to also use this for websocket inbound transport. This can help prevent some race conditions and is consistent with the other pickup approaches

[TimoGlastra]

@amanji This should fix the issue with messages being processed in parallel

[codecov-commenter]

Codecov Report

Merging #826 (6f14c57) into main (8dd7f80) will increase coverage by 0.00%.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##             main     #826   +/-   ##
=======================================
  Coverage   87.69%   87.69%           
=======================================
  Files         438      438           
  Lines       10820    10821    +1     
  Branches     1891     1834   -57     
=======================================
+ Hits         9489     9490    +1     
  Misses       1269     1269           
  Partials       62       62           

Impacted Files	Coverage Δ
packages/core/src/transport/WsOutboundTransport.ts	11.59% <50.00%> (+1.30%)	⬆️

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