12716 auto open parent components on drop

[Jondyr]

Description

To make this behaviour feel consistent these are the changes done:

• Mark new nodes as selected when added to the tree view
• Ensure all nodes are expanded/opened when a it or a child tree node is selected

This way, when either a new item is added through drag and drop or by button on the parent element (as described in #12038), the added element should be visible and expanded if applicable.

Related Issues

• 12716

• 12038

Verification

• [x] Your code builds clean without any errors or warnings
• [x] Manual testing done (required)
• [x] Relevant automated test added (if you find this hard, leave it and we'll help out)

Documentation

• [ ] User documentation is updated with a separate linked PR in altinn-studio-docs. (if applicable)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 91.47%. Comparing base (396c405) to head (e828356).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #12962 +/- ## ======================================= Coverage 91.46% 91.47% ======================================= Files 1400 1401 +1 Lines 19821 19839 +18 Branches 2395 2397 +2 ======================================= + Hits 18130 18148 +18 Misses 1427 1427 Partials 264 264 ```

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