[CI] Remove `Multi-Platform Build and Release` workflow

[nebula-aac]

Current Behavior

This workflow: https://github.com/layer5io/sistent/blob/master/.github/workflows/multi-platform.yml is disabled

Desired Behavior

Remove workflow as this is no longer needed

Implementation

Acceptance Tests

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Contributor Guides and Resources

• 🛠 Meshery Build & Release Strategy
• 🎨 Wireframes and designs for Sistent site in Figma (open invite)
• 🙋🏾🙋🏼 Questions: Layer5 Discussion Forum and Layer5 Community Slack

[pranshugupta01]

@nebula-aac If it is confirmed to be disabled, I would like to raise a PR to remove this workflow file from the repository.
So please assign it to me.

[Ajay-singh1]

@nebula-aac Is this still an issue?