Task: Fix charging-target-type not optional

[enrico-kaack-comp]

Understand the Task

Description
There are two labels on Project, Workspace and ManagedControlPlane:

• openmcp.cloud.sap/charging-target-type with value btp only for now
• openmcp.cloud.sap/charging-target value in format UUID-style sequence of 8/4/4/4/12 hexadecimal digits, separated by -

Both labels are REQUIRED on Project, optional on Workspace and ManagedControlPlane (although if one is set the other should be also set).

Any further valuable resources.

No response

What is required to accept the Task as done.

Done Criteria

• We need to add the openmcp.cloud.sap/charging-target-type to our api requests
• add openmcp.cloud.sap/charging-target-type to UI (I suggest a dropdown with just btp as only value for now)
• ensure they are required fields for Project, optional for Workspace and MCP
• ensure the format of type btp is UUID as described above
• Update/Fix tests