refactor: prevent panicking with params

[lumtis]

Description

Use GetParamsIfExist to prevent panic

Closes: #1860

[codecov]

Codecov Report

Attention: Patch coverage is 79.31034% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 49.95%. Comparing base (ce26536) to head (fa948ce).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1864      +/-   ##
===========================================
+ Coverage    49.88%   49.95%   +0.06%     
===========================================
  Files          219      220       +1     
  Lines        12712    12722      +10     
===========================================
+ Hits          6342     6355      +13     
+ Misses        5928     5925       -3     
  Partials       442      442              

Files	Coverage Δ
x/emissions/abci.go	79.34% <100.00%> (-0.23%)	⬇️
x/emissions/genesis.go	100.00% <100.00%> (ø)
x/emissions/keeper/params.go	100.00% <100.00%> (ø)
x/emissions/types/distributions.go	100.00% <100.00%> (ø)
x/observer/genesis.go	76.51% <100.00%> (ø)
x/observer/keeper/params.go	100.00% <ø> (+37.50%)	⬆️
x/observer/migrations/v4/migrate.go	77.77% <ø> (ø)
x/observer/migrations/v5/migrate.go	83.78% <100.00%> (ø)
x/observer/migrations/v7/migrate.go	100.00% <100.00%> (ø)
x/observer/keeper/ballot.go	61.36% <0.00%> (ø)
... and 1 more