[AGE-118] Observability integration without using agenta-hosted apps

[mmabrouk]

Context: Some users would like to use observability without using the application hosted in agenta to minimise latency and increase reliability

Problem: Right now instrumenting the observability requires a multitude of variable unavailable to the user when using the application

Proposed Solution:

SDK:

• Instrumenting data only requires the API_key and the app_id while all other informations becomes optional

User Workflow:

• The user creates an application in the UI
• The user visits observability
  • They see the app id and snippets to show how to instrument they data

Required changes:

• Changes to the UX to show how to instrument an application (in observability and deployment view)
• Changes to the SDK / interface between frontend and backend to allow using observability without variant_id
• Changes to the UI in dashboard, traces, spans, to make it work even without variant ids

_{From SyncLinear.com | AGE-118}