fix(auth): prevent deadlock in updateUser

[ForestLinSen]

🔍 Description

What changed?

Modified the _updateUser method in src/GoTrueClient.ts to execute the _notifyAllSubscribers call asynchronously.

Why was this change needed?

This fixes a deadlock issue where updateUser would hang indefinitely despite a successful server response.

I've got the same issue as issue #1441 . After digging into it, I found that the issue is because updateUser acquires a lock, and after success, it calls and awaits _notifyAllSubscribers. However, the lock is unavailable for the subscribers. So the subscriber waits for the lock, and updateUser waits for the subscriber => Deadlock

Closes #1441

📸 Screenshots/Examples

🔄 Breaking changes

• This PR contains no breaking changes

📋 Checklist

• I have read the Contributing Guidelines
• My PR title follows the conventional commit format: <type>(<scope>): <description>
• I have run npx nx format to ensure consistent code formatting
• I have added tests for new functionality (if applicable)
• I have updated documentation (if applicable)

📝 Additional notes

[mandarini]

@ForestLinSen thank you for the contribution! I went with this solution instead (#2014) because it matches existing patterns!

Once again, thank you for taking the time to contribute to Supabase! You're helping us make the tool better! 💚