🚀 Feature: Add Auto-Completion for Headers

### 🔖 Feature description

Similar to Postman,
Please add a auto-completion support for adding common/generic headers on the dashboard.

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Relevant UI -

### 🎤 Pitch

Current used headers & body are saved for repeated usage, aware of that but this would enhance the UX incase of appwrite restart, session delete and re-login.

### 👀 Have you spent some time to check if this issue has been raised before?

- [X] I checked and didn't find similar issue

### 🏢 Have you read the Code of Conduct?

- [X] I have read the [Code of Conduct](https://github.com/appwrite/.github/blob/main/CODE_OF_CONDUCT.md)