Allow tests to fail based on a exitOnEmpty flag being set.

[kevbite]

This pull request introduces a new feature that allows the workflow to fail if no tests are found in the test report, controlled by a new exit-on-empty option. This option is available both as a GitHub Action input and as a CLI flag. The implementation includes updates to documentation, input parsing, and core logic to support this feature.

New "exit on empty" feature:

• Added a new exit-on-empty input/flag to both the GitHub Action (action.yml) and CLI, allowing users to configure the workflow to fail if no tests are found in the report. [1] [2] [3] [4]
• Updated input handling functions (getInputs and getCliInputs) and the Inputs interface to include the new exitOnEmpty property. [1] [2] [3]
• Implemented the exitActionOnEmpty function, which sets the workflow to failed if the test report contains zero tests, and integrated it into both action and CLI execution flows. [1] [2] [3] [4] [5]

Documentation updates:

• Updated README.md to document the new exit-on-empty option, describing its purpose and default value.

#219

[Ma11hewThomas]

Thank you @kevbite, to be included in next release