Bounty tests

[0311xuyang]

Closes: #566
Related: #XXX

Description

• Add e2e test about bounty module
• Change query option on test from http api to grpc client

---

For contributor use:

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer

---

For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
• Reviewers assigned
• Squashed all commits, uses message "Merge pull request #XYZ: [title]"

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (bounty@15c935d). Click here to learn what that means.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff            @@
##             bounty     #591   +/-   ##
=========================================
  Coverage          ?   41.39%           
=========================================
  Files             ?      147           
  Lines             ?    13775           
  Branches          ?        0           
=========================================
  Hits              ?     5702           
  Misses            ?     7547           
  Partials          ?      526           

[yoongbok-lee]

I guess this is more like a general integration test suite but still LGTM