Change PhotoPlaceholder component to be more reusable

[pplaskie]

📝 Description

PhotoPlaceholder was already used in geti to handle things that do not have email and it is also used in other geti applications - email is used for color generation.

I've changed email to indicator attribute to have more sense in other use cases than handling users.

Note: after merging this pr component in other applications have to be updated

✨ Type of Change

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• 🐞 Bug fix – Non-breaking change which fixes an issue
• 🚀 New feature – Non-breaking change which adds functionality
• 🔨 Refactor – Non-breaking change which refactors the code base
• 💥 Breaking change – Changes that break existing functionality
• 📚 Documentation update
• 🔒 Security update
• 🧪 Tests

🧪 Testing Scenarios

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• ✅ Tested manually
• 🤖 Run automated end-to-end tests

✅ Checklist

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• 🔍 PR title is clear and meaningful
• ✍️ PR description clearly explains the changes and their reason
• 📝 I have linked the PR to the corresponding GitHub Issues, if any
• 💬 I have commented my code, especially in hard-to-understand areas
• 📄 I have made corresponding changes to the documentation
• ✅ I have added tests that prove my fix is effective or my feature works