Change default value of failure_alert to false for project users

[mausam-giri]

Description

This PR [Changes] - default value of failure_alert to false for project users

Closes #__

Validation steps

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1. Run migration in the development
2. Check the dashboard for the option field Feature Alert

Additional notes for the reviewer

1. (Is there anything else the reviewer should know or look out for?)

AI Usage

Please disclose how you've used AI in this work (it's cool, we just want to know!):

• Code generation (copilot but not intellisense)
• Learning or fact checking
• Strategy / design
• Optimisation / refactoring
• Translation / spellchecking / doc gen
• Other
• I have not used AI

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Pre-submission checklist

• I have performed a self-review of my code.
• I have implemented and tested all related authorization policies. (e.g., :owner, :admin, :editor, :viewer)
• I have updated the changelog.
• I have ticked a box in "AI usage" in this PR

[taylordowns2000]

This is wonderful @mausam-giri ! Thank you! ❤️ Two small requests:

1. Please update the PR language itself to include the words "closes #3517" and indicate which ways you've used AI to prepare the PR (you'll find all this stuff in the PR template)
2. Please add a small test (or an assertion to the current test) to show that when collaborators are added, they now default to false. The current tests here are in the project_live_tests.ex file around line 540