Clarify provider release testing status issue creation instructions

[shahar1]

Human Summary

This PR improves the flow of creating the github issue and carrying over the checkmarks as part of the providers release.

AI Summary

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This pull request updates the provider release workflow documentation in `dev/README_RELEASE_PROVIDERS.md` to clarify and improve the process for generating, editing, and publishing provider testing issues on GitHub. The main focus is on making the workflow more robust against GitHub's URL length limitations, supporting local editing, and ensuring checkmarks are properly carried over between waves.

Documentation improvements to provider issue workflow:

• Recommends generating the provider testing issue body locally to a file (files/provider_issue.md) before publishing, allowing for local modifications and avoiding GitHub URL length limitations.
• Adds clear instructions for filtering out noisy PRs from the generated issue using the --excluded-pr-list option.
• Documents how to carry over completed checkmarks from the previous wave’s issue, including platform-specific sed commands for macOS and GNU/Linux.
• Details the steps for creating or updating the GitHub issue from the local file, including how to update an existing issue with the carried-over checkmarks.
• Improves overall workflow clarity and robustness by breaking the process into clear steps and emphasizing the importance of local file editing before publishing. [1] [2]

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