Dashboard add `Retry` to validate window too

**Describe the problem you have/What new integration you would like**
Install window has a `Retry` button which you can press after fixing the config in an external editor. Wish is to have the same functionality and behavior for Validate window.

**Please describe your use case for this integration and alternatives you've tried:**
We use external editors (Pluma and Notepad++) to edit the yaml configs, and we use Validate option in the dashboard to check if config is correct. Would be nice not to have to close and re-open this window every time after a change has been made.

Validate is very useful as one might not want to do the install immediately, but would like to finalize validations first, and do the installs at a later stage.

**Additional context**

The request concerns the Dashboard Validate window and its existing Retry behavior in the Install window. Start by locating those two window entry points and any validation tests, then verify that Validate can be rerun after an external YAML edit without closing the window. Done means the Validate window offers matching Retry behavior and the flow is covered by tests.

Written by the indexing model from the issue text.