IDE-306 Draft PR

[dorastr]

IDE-306 (https://catrobat.atlassian.net/browse/IDE-306)
When executing the cast project the program crashes because of Nullpointer Exceptions.
Changes:

• update cast version
• synchronisation in addStageViewToLayout()

Your checklist for this pull request

Please review the contributing guidelines and wiki pages of this repository.

• Include the name of the Jira ticket in the PR’s title
• Include a summary of the changes plus the relevant context
• Choose the proper base branch (develop)
• Confirm that the changes follow the project’s coding guidelines
• Verify that the changes generate no compiler or linter warnings
• Perform a self-review of the changes
• Verify to commit no other files than the intentionally changed ones
• Include reasonable and readable tests verifying the added or changed behavior
• Confirm that new and existing unit tests pass locally
• Check that the commits’ message style matches the project’s guideline
• Stick to the project’s gitflow workflow
• Verify that your changes do not have any conflicts with the base branch
• After the PR, verify that all CI checks have passed
• Post a message in the catroid-stage or catroid-ide Slack channel and ask for a code reviewer
  ](https://catrobat.atlassian.net/browse/IDE-306)

[sonarqubecloud]

Quality Gate failed

Failed conditions
B Maintainability Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

Catch issues before they fail your Quality Gate with our IDE extension SonarQube for IDE