Feature
## What is the current behavior?
Functions page on self-hosted differs from Platform
## What is the new behavior?
Adds the possibility to try/test functions in Self-Host version.
## Summary by CodeRabbit
* **Bug Fixes**
* Improved edge function URL validation so testing works reliably both
on-platform and off-platform, including proper URL handling for local
setups.
* **UI Improvements**
* Moved the Test button in the edge functions interface for more
consistent layout while preserving its behavior.
* **Tests**
* Expanded tests to cover platform-aware URL validation scenarios.
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Co-authored-by: Charis Lam <26616127+charislam@users.noreply.github.com>
