fix: expose error detail when swap simulation fails

[dandanlen]

This fixes an issue observed during the recent upgrade, when liquidity is low. Error messages were being erased due to the implementation of DispatchError.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 10 lines in your changes missing coverage. Please review.

Project coverage is 72%. Comparing base (f969c92) to head (f6a87e4).

Files with missing lines	Patch %	Lines
state-chain/runtime/src/runtime_apis.rs	0%	5 Missing ⚠️
state-chain/custom-rpc/src/lib.rs	0%	3 Missing ⚠️
state-chain/runtime/src/lib.rs	0%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@          Coverage Diff           @@
##            main   #5485    +/-   ##
======================================
- Coverage     72%     72%    -0%     
======================================
  Files        495     495            
  Lines      88168   88049   -119     
  Branches   88168   88049   -119     
======================================
- Hits       63152   62975   -177     
- Misses     22449   22508    +59     
+ Partials    2567    2566     -1     

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[syan095]

Is there still value in keepping the dispatcherror::Others variant? I believe that the original intent was for a string message to be passed through RPC back to the user. Maybe we should just replace the Other with your new type.

[syan095]

Also a nitpick - the word "adhoc" isn't very clear on its intended purpose, or the difference between this and the other 2 variant. Maybe something like "message" or "string" or "utf8" would be clearer?

[syan095]

Is there still value in keepping the dispatcherror::Others variant?

I suppose the variant is just there to blanket cover all the other cases (non-module, non-str)

[syan095]

Nice. I'm already using this in the Vault swap branch!