Fix Topic copy with children

[vlakn]

When creating a topic from another ITopic also create copies of the topics children and bind these to the newly created topic instead of moving the children from the original topic to new newly created one. This fixes the issue of not returning the right parent when calling getChildren() for a child topic.

Contributes to
#525

Fixes https://bugs.eclipse.org/bugs/show_bug.cgi?id=210024

[github-actions]

Test Results

    54 files  +   11      54 suites  +11   35m 7s ⏱️ + 5m 48s
 4 558 tests +    2   4 535 ✅ +    4   23 💤  - 2  0 ❌ ±0 
12 270 runs  +2 507  12 111 ✅ +2 499  159 💤 +8  0 ❌ ±0 

Results for commit 4c400c2. ± Comparison against base commit a329aa5.

♻️ This comment has been updated with latest results.

[fedejeanne]

Thank you for the contribution @vlakn ! The change looks good and I think there is no harm in applying it. I have some minor improvements (see comments) and also, do you have some custom formatting/clean-up options enabled in your workspace? I ask only because I see a lot of unrelated changes (nothing against them, it just makes it more difficult to review).

Can you please also mention the tests that are supposed to be fixed by this PR in the commit text?

[vlakn]

Thank you for the review and the feedback @fedejeanne!
I’ve applied the suggested improvements from your comments and updated the PR description to explicitly mention the bugzilla issue that this change is intended to fix.
Regarding formatting: I don’t think i have any custom formatter or clean‑up rules enabled in my workspace. The changes you’re seeing were produced by the built‑in default Eclipse formatter only. That said, I understand how the unrelated formatting changes can make reviewing harder—thanks for pointing it out.