Add -race flag option on test run

[M-T3K]

Note: Apologies, I found no PR format established for the project.

This PR concerns the use of the -race flag to catch further concurrency issues when executing go code.

Consequences and implications: using the -race flag causes additional overhead at runtime, meaning tests take longer. Hence why this is done only on tests and in a way that is separate from the default test run. Therefore, it can be disabled and enabled at will. It has no impact on release execution.

Implementation:

• I propose a separate option in the makefile that is different from default test that is called test-race which runs tests with golang's -race flag.
• Additionally, the ci file has been updated to also run this -race flag, separately from the tests themselves, so that commits also report potential race conditions & other issues.

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Note

Low Risk
Low risk: CI/Makefile-only change that increases test coverage via the Go race detector, with the main impact being longer CI/test runtimes.

Overview
Adds a dedicated test-race job to GitHub Actions CI to run go test -race ./... alongside the existing unit tests.

Extends the Makefile with a matching test-race target so developers can run race-detected tests locally without changing the default make test behavior.

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[JesseHerrick]

Good thinking! I was using this locally to catch race conditions, but sounds like a good addition to the CI.