Chore(x/auction): Unit test for auction module

[sontrinh16]

This issue tracks the progress and tasks related to the integration tests for the auction module

Tasks

Keeper tests

• Implement test for CreateAuction
• Implement test for AddBidEntry
• Implement test for CancelBidEntry
• Implement test for DeleteAuction

Msg server tests

• Implement test for MsgBid
• Implement tests for MsgCancelBid

BeginBlocker

• Implement tests for BeginBlocker
• Create Auction when reaching new auction period
• Handle bid entry
• Handle auction clean up