feat: adds enterprise license check

[gupta-piyush19]

What does this PR do?

Adds enterprise license check by calling the formbricks enterprise server for validation

Fixes

• License check logic

How should this be tested?

• set IS_FORMBRICKS_CLOUD = 0 in .env
• set a valid ENTERPRISE_LICENSE_KEY provided by @jobenjada or @mattinannt
• check the enterprise license status in settings(/settings/enterprise)

Checklist

Required

• Filled out the "How to test" section in this PR
• Read How we Code at Formbricks
• Self-reviewed my own code
• Commented on my code in hard-to-understand bits
• Ran pnpm build
• Checked for warnings, there are none
• Removed all console.logs
• Merged the latest changes from main onto my branch with git pull origin main
• My changes don't cause any responsiveness issues

Appreciated

• If a UI change was made: Added a screen recording or screenshots to this PR
• Updated the Formbricks Docs if changes were necessary

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Name	Status	Preview	Comments	Updated (UTC)
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[github-actions]

Thank you for following the naming conventions for pull request titles! 🙏

[jonas-hoebenreich]

Would it be possible to implement a fallback that ensures that the license is not deactivated by accident? When the the key is recognized as not valid due to an error (e.g. ee.formbricks.com has an outage or is buggy) suddenly all users will have admin rights and can do stupid things.
Possible solutions to ensure that a downtime of the license server does not affect all Enterprise installations:

• Check the license status every hour, but only return invalid if it has never been valid in the past 6 hours
• Show annoying banners in the backend to warn users that the licence key is invalid and enterprise features will be deactivated soon

[gupta-piyush19]

Thanks, @jonas-hoebenreich, for the suggestion.
It makes sense to have a fault-tolerant system. I am thinking of adding a cached value for licence validity, such that if the enterprise server returns an erroneous value, we can rely on the cached value for up to 24 hours.