chore: add more testing around asset class

[cmwylie19]

Description

The assets class does not have unit tests. The purpose of this PR is to add coverage to ensure the class is working as expected.

Due to the use of dependency injection we are loosely helper functions with the method and functions on the assets class that rely on members of the assets class. Due to that, the intent of this PR is to ensure those injected functions are being with the correct members of the assets class and to hedge against accidentally change by ensuring certain functions are called a certain number of times.

Related Issue

Fixes #1655

Relates to #

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Unit, Journey, E2E Tests, docs, adr added or updated as needed
• Contributor Guide Steps followed

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 82.04%. Comparing base (4a85ad0) to head (542ab0c).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1753      +/-   ##
==========================================
+ Coverage   81.10%   82.04%   +0.94%     
==========================================
  Files          50       51       +1     
  Lines        2127     2211      +84     
  Branches      430      436       +6     
==========================================
+ Hits         1725     1814      +89     
+ Misses        400      395       -5     
  Partials        2        2              

Files with missing lines	Coverage Δ
src/lib/assets/assets.ts	100.00% <ø> (ø)
src/lib/assets/index.ts	76.47% <ø> (ø)

... and 2 files with indirect coverage changes

[samayer12]

There's room for improvement around how we generate test data, and some of the tests may run the risk of being tied too closely to implementations. However, this is an improvement over previously untested code. Any future refactors of the test suite will have a good starting point 👍