optional endpoint for metrics aggregator

[denis-yuen]

Description
Add default for endpoint override to allow it to pass missing properties check

Review Instructions
Can run test manually

Issue
https://ucsc-cgl.atlassian.net/browse/SEAB-7290

Security
None

Please make sure that you've checked the following before submitting your pull request. Thanks!

• Check that you pass the basic style checks and unit tests by running mvn clean install in the project that you have modified (until https://ucsc-cgl.atlassian.net/browse/SEAB-5300 adds multi-module support properly)
• Ensure that the PR targets the correct branch. Check the milestone or fix version of the ticket.
• If you are changing dependencies, check with dependabot to ensure you are not introducing new high/critical vulnerabilities
• If this PR is for a user-facing feature, create and link a documentation ticket for this feature (usually in the same milestone as the linked issue). Style points if you create a documentation PR directly and link that instead.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 15.83%. Comparing base (447a154) to head (1e598fb).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@            Coverage Diff             @@
##             develop     #543   +/-   ##
==========================================
  Coverage      15.83%   15.83%           
  Complexity       100      100           
==========================================
  Files             40       40           
  Lines           2337     2337           
  Branches         186      186           
==========================================
  Hits             370      370           
  Misses          1943     1943           
  Partials          24       24           

Flag	Coverage Δ
metricsaggregator	10.48% <100.00%> (ø)
toolbackup	15.83% <100.00%> (ø)
tooltester	10.48% <100.00%> (ø)
topicgenerator	10.48% <100.00%> (ø)

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