Kiota VS Code Extension should only show the actions the user can perform

Today, Kiota VS Code extension shows in the API Explorer panel all the different actions one can perform:


However, for a better experience, Kiota should only show the actions one can perform, so we don't overwhelm the user with a UI with a lot of icons that actually don't do anything/don't apply.

## Acceptance Criteria

1. For operations, Kiota should only show Add and Remove actions (Add all and remove all are not relevant for this scenarios)
2. For operations, after adding the operation, the `Add` button should be disabled and only `Remove` button be enable
3. For nodes, the `Add` and `Remove` buttons should show both "Add operations" and "Add all"
4. For nodes, after adding operations, only "Add all" should be enabled
5. After adding all, `Add` button should be disabled, since only remove actions can be performed
6. When a path only has operations, we should only show `Add operations` option
7. When a path there is no operations but there are other nodes only show `Add all` option

Start by locating the Kiota VS Code extension's API Explorer panel and the code that renders its Add and Remove actions. Review how operation and node state is determined, then manually exercise the acceptance criteria to verify that only applicable actions are shown and enabled.

Written by the indexing model from the issue text.