test: x/oracle unit test cleanup

[adamewozniak]

Description

Just cleanup + minor additions to our oracle module unit tests

progress on: #661

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Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added appropriate labels to the PR
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

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your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[codecov-commenter]

Codecov Report

Merging #781 (ec7e927) into main (a176fb2) will decrease coverage by 0.32%.
The diff coverage is 13.19%.

@@            Coverage Diff             @@
##             main     #781      +/-   ##
==========================================
- Coverage   48.03%   47.70%   -0.33%     
==========================================
  Files          64       64              
  Lines        9329     9426      +97     
==========================================
+ Hits         4481     4497      +16     
- Misses       4581     4662      +81     
  Partials      267      267              

Impacted Files	Coverage Δ
ante/fee.go	93.61% <ø> (ø)
ante/spam_prevention.go	61.76% <ø> (ø)
x/ibctransfer/keeper/keeper.go	77.92% <ø> (ø)
x/leverage/abci.go	0.00% <ø> (ø)
x/leverage/client/cli/proposal.go	72.72% <ø> (ø)
x/leverage/client/cli/query.go	0.00% <ø> (ø)
x/leverage/client/cli/tx.go	0.00% <ø> (ø)
x/leverage/client/tests/suite.go	100.00% <ø> (ø)
x/leverage/client/tests/util.go	87.69% <ø> (ø)
x/leverage/genesis.go	50.00% <ø> (ø)
... and 36 more