fix(x/callback): error code was identified incorrectly

[spoo-bar]

• adding new error code for contract execution error
• fixing issue with how the error code was assigend by the callback module on various callback errors
• update the callback abci tests to use chain.NextBlock() instead of callbackabci.EndBlocker as the former would also call cwerrors endblocker

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 64.63%. Comparing base (a03ff86) to head (dc6d724).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #552 +/- ## ========================================== + Coverage 64.56% 64.63% +0.06% ========================================== Files 120 120 Lines 5975 5977 +2 ========================================== + Hits 3858 3863 +5 + Misses 1901 1899 -2 + Partials 216 215 -1 ```

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