disabled double submit while creating a channel

[AllanOXDi]

Summary

This PR fixes the double submit error while creating a new channel.
Ref #3833

Manual verification steps performed

Step 1: Try to create a new channel from studio, and observe what is happening on clicking create button.
Step 2: You may also try on a slow network connectivity

Contributor's Checklist

PR process:

• If this is an important user-facing change, PR or related issue the CHANGELOG label been added to this PR. Note: items with this label will be added to the CHANGELOG at a later time
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• The docs label has been added if this introduces a change that needs to be updated in the user docs?
• If any Python requirements have changed, the updated requirements.txt files also included in this PR
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• Migrations are safe for a large db

Studio-specifc:

• All user-facing strings are translated properly
• The notranslate class been added to elements that shouldn't be translated by Google Chrome's automatic translation feature (e.g. icons, user-generated text)
• All UI components are LTR and RTL compliant
• Views are organized into pages, components, and layouts directories as described in the docs
• Users' storage used is recalculated properly on any changes to main tree files
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Testing:

• Code is clean and well-commented
• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
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• Any new interactions have been added to the QA Sheet
• Critical and brittle code paths are covered by unit tests

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Reviewer's Checklist

This section is for reviewers to fill out.

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[bjester]

I'm not sure it's worth doing, but if the endpoint returns this 409 status code, then perhaps the frontend can redirect to the channel page like it does with the normal 201 response?

[AllanOXDi]

I think our main objective while implementing this was to try and throw a more meaningful error when creating a channel that the Id already exists.

[bjester]

Okay! I was simply thinking about whether the change was as meaningful to the end-user as it is to us, since it would silence error reports on our end.

[AllanOXDi]

I agree! But again, do we need a redirect when double creation happens? Or we could try and find a way of letting the user know if double creation happened.

[bjester]

I think it's very unlikely a user encounters this scenario submitting the form. But if they somehow did encounter it, or perhaps even a gateway timeout 502 error, I don't think the frontend would give the user notice one of those errors occurred, meaning the submit button would be forever disabled without any indication to the user.