NO-TICKET - Auto PR for rdkcentral/meta-rdk 387

[rdkcm-rdke]

Details: ## Description
This PR updates the middleware_change_request.yml issue template to improve the user experience and fix GitHub validation errors.

Changes

• Replaced separate checkbox and input field pairs with a single textarea for the Definition of Done (DoD) checklist
• Added comprehensive guidance text explaining the DoD requirements
• Added warning about NOT providing proprietary information:
  • No links to internal Automatics/CI builds
  • No links to internal Confluence pages
  • No Comcast/Sky proprietary or confidential information
• Instructed users to add proprietary information to JIRA tickets only
• Maintains all DoD items with markdown checkboxes and detail fields in the textarea
• Reduces visual spacing between DoD items for better UX

Benefits

• Single textarea is easier to fill out than multiple checkbox/input pairs
• Eliminates GitHub validation errors for empty labels
• Better user experience with less spacing
• Clear guidance on proprietary vs public information

Testing

The template will be automatically validated by GitHub when this PR is merged.

List of PRs and Repositories Involved:

• Repository: rdkcentral/meta-rdk, Merge Commit SHA: 64e1ae3174fde67fd8509bddcf32f0925932d58d