refactor(uart): Refactor UART test to work with any number of UARTs

[lucasssvaz]

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⚠️	The **target branch** for this Pull Request **must be the default branch** of the project (`master`). If you would like to add this feature to a different branch, please state this in the PR description and we will consider it.

👋 Hello lucasssvaz, we appreciate your contribution to this project!

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Test Results

 62 files   62 suites   5m 56s ⏱️
 21 tests  15 ✅ 0 💤 6 ❌
154 runs  147 ✅ 0 💤 7 ❌

For more details on these failures, see this check.

Results for commit 5b2b9fc.

♻️ This comment has been updated with latest results.