Telemetry: Publish client-version if possible

### Problem

It helps us make better decision in terms of code maintenance if we have the client . For example, this PR https://github.com/microsoft/GitHub-Copilot-for-Azure/pull/1846 script has a fallback logic to support toolArgs for copilot-cli. it would help to know how many users are still using older copilot-cli version and when the number is small, we can cleanup the code to stop supporting toolArgs and only rely on copilot_cli env variable.

### Desired Solution

ability to publish plugin-version telemetry and update dashboards as appropriate

### Alternatives and Workarounds

_No response_

### Impact

_No response_

### Additional Context

_No response_

Start with the script discussed in PR 1846 and inspect the existing telemetry publication and dashboard setup. Identify how the plugin version can be reported alongside current telemetry, then verify that the dashboards expose the version data needed to measure older copilot-cli usage.

Written by the indexing model from the issue text.