## Description
Starts work on the Multi Pane IDE that would be behind a feature flag
right now. We will continue work on this behind the scenes
> New shiny Multi Pane layout that will be unwrapped after a few months
Fixes#19210
## Type of change
- New feature (non-breaking change which adds functionality)
- Breaking change (fix or feature that would cause existing
functionality to not work as expected)
## How Has This Been Tested?
> Please describe the tests that you ran to verify your changes. Provide
instructions, so we can reproduce.
> Please also list any relevant details for your test configuration.
> Delete anything that is not important
- Manual
- Jest
- Cypress
### Test Plan
> Add Testsmith test cases links that relate to this PR
### Issues raised during DP testing
> Link issues raised during DP testing for better visiblity and tracking
(copy link from comments dropped on this PR)
## Checklist:
### Dev activity
- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my own code
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] PR is being merged under a feature flag
### QA activity:
- [ ] Test plan has been approved by relevant developers
- [ ] Test plan has been peer reviewed by QA
- [ ] Cypress test cases have been added and approved by either SDET or
manual QA
- [ ] Organized project review call with relevant stakeholders after
Round 1/2 of QA
- [ ] Added Test Plan Approved label after reveiwing all Cypress test
