test: add event checking to TestInstantiateContract2

[da1suk8]

Description

TestInstantiateContract2

https://github.com/Finschia/wasmd/blob/main/docs/proto/proto-docs.md#msginstantiatecontract2

This PR adds an integration test for TestInstantiateContract2.

This test is based on https://github.com/CosmWasm/wasmd/blob/33df4aeaaa419f6aad07b94d64c0423bee0a2d21/x/wasm/keeper/msg_server_integration_test.go#L899-L976

Checklist:

• I followed the contributing guidelines and code of conduct.
• I have added a relevant changelog to CHANGELOG.md
• I have added tests to cover my changes.
• I have updated the documentation accordingly.
• I have updated API documentation client/docs/swagger-ui/swagger.yaml

[codecov]

Codecov Report

Merging #74 (5817116) into main (87f69d6) will increase coverage by 0.19%.
The diff coverage is n/a.

❗ Current head 5817116 differs from pull request most recent head a300e47. Consider uploading reports for the commit a300e47 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #74      +/-   ##
==========================================
+ Coverage   62.38%   62.57%   +0.19%     
==========================================
  Files          80       80              
  Lines        9966     9966              
==========================================
+ Hits         6217     6236      +19     
+ Misses       3425     3403      -22     
- Partials      324      327       +3     

see 1 file with indirect coverage changes