MG-42 - Remove creation of a channel with a parent channel

[ianmuchyri]

What type of PR is this?

• [ ] Refactor
• [ ] Feature
• [x] Bug Fix
• [ ] Optimization
• [ ] Documentation Update
• [ ] Dependency Update

What does this do?

Removes the ability for a user to create a channel with another channel as the parent. This is because this is not supported on the magistrala core.

Which issue(s) does this PR fix/relate to?

• Related Issue #
• Resolves #42
• Resolves #44

Have you included tests for your changes?

• [ ] Yes
• [ ] No, and this is why:

Did you document any new/modified functionality?

• [ ] Yes
• [ ] No, and this is why:

Notes

[codecov-commenter]

Codecov Report

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

:exclamation: No coverage uploaded for pull request base (main@fbf688f). Click here to learn what that means.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #250 +/- ## ======================================= Coverage ? 81.00% ======================================= Files ? 3 Lines ? 179 Branches ? 0 ======================================= Hits ? 145 Misses ? 18 Partials ? 16 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.