Show "Generate" or "Regenerate" button in the API Explorer based on the user flow

[maisarissi]

Challenge

As part of our integrated history with Teams Toolkit when generating API Plugin for existing APIs, we are seeing a drop in how many users go back to TTK after landing in Kiota.
One of our assumptions is that folks are lost and don't know what to do to complete the flow. To increase the number of users being successful when coming from TTK, we should do some adjustments in the UI to try to make things clearer, even more for new users.\

Proposal

Add a label after the Generate/Regenerate button and show the right button based on the user flow.

When the user is loading a new API in the API Explorer, we should show the Generate button and label like the image below:

When the user is editing an existing plugin/client, we should replace the Generate with a Regenerate button and label.

Acceptance Criteria

1. The Generate/Regenerate button should only be enabled and there is at least one endpoint selected.
2. When there is no plugin/client loaded in the API Explorer, we should show the Generate button and label.
3. When selecting an existing plugin/client to edit it, we should show a Regenerate button and label rather than Generate. The regenerate icon should perform the plugin generation with the new parameters based on the user selection.
4. All the existing regeneration behaviors and features, as an example the Kiota should warn the user when re-generating that all changes did manually by them will be overridden #5303), should continue the same.