Snyk Analyser: Test Connection Button

### Current Behavior

Dependency-Track v4.7.0 introduced Beta support for Snyk Analyser.

This requires configuration of `Organization ID` and `API token`, as well as `API Version`

I thought I had valid values for all three parameters and yet nothing seemed to happen. I saw nothing in logs recording succesful configuration (or an error) and no snyk synch running (although that woul have been hours later, possibly).

### Proposed Behavior

Add a button to "Test Connection", providing feedback that all is working OK... or giving details on any problems.

If possible, add additional logging.

This issue is similar to logged to requests for Test Connection buttons for:

* OSS Index: #265
* GitHub: #1670

### Checklist

- [X] I have read and understand the [contributing guidelines](https://github.com/DependencyTrack/dependency-track/blob/master/CONTRIBUTING.md#filing-issues)
- [X] I have checked the [existing issues](https://github.com/DependencyTrack/dependency-track/issues) for whether this enhancement was already requested