runTests tool description confuses agents

- VS Code Version: 1.130.0
- OS Version: Win 11
- Feature (e.g. agent/edit/ask mode): agent mode
- Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): not relevant
- Logs: None

Steps to Reproduce:

1. Ask agent to run integration tests. It gets confused due to tool description stating "unit tests" whereas the test explorer can contain any type of tests like integration, e2e, etc.

https://github.com/microsoft/vscode/blob/792a995058e67c6b4f1e63384165f98827de2eb5/src/vs/workbench/contrib/testing/common/testingChatAgentTool.ts#L78
Description of tool should be generalized and not mention specific type of test.