Fixed #20038 loading icon disappearing before background process completes for Braintree payment in Admin

[ghost]

Description (*)

Fixed Issues (if relevant)

1. loading icon disappearing before background process completes for braintree payment (Admin order) #20038: loading icon disappearing before background process completes for braintree payment (Admin order)

Manual testing scenarios (*)

1. Login to the Admin
2. Create a order for a customer
3. Use Credit Card(BrainTree) payment method
4. Click 'Submit Order' button
5. Full page loader should be visible until user is redirected to succes page or error occurs.

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[m2-assistant]

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[magento-cicd2]

All committers have signed the CLA.

[ronak2ram]

Hi @kunal-rtpl, please, sign CLA, otherwise, we can't process your pull request.

[ghost]

Hi @kunal-rtpl, please, sign CLA, otherwise, we can't process your pull request.

Hi ronak2ram, signed

[magento-engcom-team]

Hi @sidolov, thank you for the review.
ENGCOM-5324 has been created to process this Pull Request

[engcom-Delta]

✔️ QA Passed

[m2-assistant]

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