debezium/dbz#1725 fix: Improve loading state-management

[gmarav05]

Fixes debezium/dbz#1725

Description

This PR improves the initial loading state management in the Platform UI by addressing the following:

• Removed "Loading" text from the initial application load window by updating the Suspense fallback in main.tsx.
• Implemented retry logic: Configured the global QueryClient with retry: 3. This ensures that in case of network issues, the UI will attempt to fetch data 3 times before displaying a network failure message, rather than showing a loading state indefinitely.
• Unified Loading UX: Removed hardcoded and translated "Loading..." text from major page components (Pipelines, Sources, Destinations, Connections, and Transforms) while retaining the PatternFly Spinner for visual feedback.
• Updated Tests: Adjusted unit tests to verify loading states by checking for the progressbar role (associated with the Spinner component) instead of searching for the now-removed text.

PR Checklist

• I have read the contribution guidelines and the governance document on PR expectations.
• Minimal changes to code not directly related to your change (e.g. no unnecessary formatting changes or refactoring to existing code)
• One feature/change per PR unless tightly coupled
• Do a rebase on upstream main

[github-actions]

Hi @gmarav05, thanks for your contribution. Please prefix the commit message(s) with the debezium/dbz#xxx GitHub issue key.

[gmarav05]

Hello @mfvitale, @Naros , @indraraj

I think this is ready for the review.

Please let me know if any changes are required.

[mfvitale]

@gmarav05 Are you able to record a video of the result?

[gmarav05]

@mfvitale No, I did not record it. I will record it and post it here today. Thanks for letting me know.

[indraraj]

@gmarav05 Please rebase onto the latest main. Plus these are listing pages that you covered and have pooling, retry is not needed here instead limit polling after a few failed attempts and show an appropriate message to the user.