fix: fix x/collection ModifyContract

[0Tech]

Description

closes: #797

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 #798 (59700ac) into rc9/v0.46.0 (6792efe) will increase coverage by 0.06%.
The diff coverage is 100.00%.

Additional details and impacted files

@@               Coverage Diff               @@
##           rc9/v0.46.0     #798      +/-   ##
===============================================
+ Coverage        62.15%   62.22%   +0.06%     
===============================================
  Files              877      877              
  Lines            99419    99419              
===============================================
+ Hits             61796    61860      +64     
+ Misses           34019    33927      -92     
- Partials          3604     3632      +28     

Impacted Files	Coverage Δ
x/collection/keeper/supply.go	89.11% <100.00%> (ø)
x/token/validation.go	87.27% <0.00%> (+1.81%)	⬆️
x/token/msgs.go	52.47% <0.00%> (+3.04%)	⬆️
x/collection/msgs.go	55.65% <0.00%> (+7.73%)	⬆️
x/token/token.go	100.00% <0.00%> (+50.00%)	⬆️