BUGFIX: Migration with two UpdateRootNodeAggregateDimensions cannot be published

[mhsdesign]

WIP, because adds only failing test.

its only possible to update two root node aggregates when writing the commands directly in live.

Otherwise, a restriction prevents this:

the content stream cs-identifier already contained nodes in dimension space point {"language":"fr"} - this is not allowed.

See 7122d71 which was part of #5514 as to why restriction exists.

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Checklist

• Code follows the PSR-2 coding style
• Tests have been created, run and adjusted as needed
• The PR is created against the correct branch:
  • If it's a bugfix, use the lowest maintained branch which has the bug
  • If it's a non-breaking feature, use the branch of the next version (might be either minor or major)
  • If it's a breaking feature it should typically go into the next major version
• Reviewer - PR Title is brief but complete and starts with FEATURE|TASK|BUGFIX
• Reviewer - The first section explains the change briefly for change-logs
• Reviewer - Breaking Changes are marked with !!! and have upgrade-instructions