[Bugfix] Register wasm queriers after staking keeper initialization

[yun-yeo]

Summary of changes

• Register wasm queriers after initializing staking keeper

close #428

Report of required housekeeping

• Github issue OR spec proposal link
• Wrote tests
• Updated API documentation (client/lcd/swagger-ui/swagger.yaml)
• Added a relevant changelog entry: clog add [section] [stanza] [message]

---

(FOR ADMIN) Before merging

• Added appropriate labels to PR
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)
• Confirm added tests are consistent with the intended behavior of changes
• Ensure all tests pass

[codecov]

Codecov Report

Merging #427 (82923ae) into develop (4ae926c) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #427   +/-   ##
========================================
  Coverage    67.52%   67.52%           
========================================
  Files          117      117           
  Lines         5053     5053           
========================================
  Hits          3412     3412           
  Misses        1427     1427           
  Partials       214      214           

Impacted Files	Coverage Δ
app/app.go	92.04% <100.00%> (ø)