Description:
We need to update the 3scale 2.15 documentation to include a deprecation note about the threescale-wasm-auth module used for integration with OpenShift Service Mesh.

Context:
The threescale-wasm-auth module is deprecated and is no longer supported starting from OpenShift Service Mesh 3. While it remains available in earlier versions, users should anticipate its future decommissioning and avoid relying on it for new deployments. This aligns with the official Service Mesh documentation, which lists it under unsupported add-on configurations.

Documentation to update:

• Chapter 11. The 3scale API Management WebAssembly module
  https://docs.redhat.com/en/documentation/red_hat_3scale_api_management/2.15/html/operating_red_hat_3scale_api_management/threescale-webassembly-module

Proposed content to add (as an Important note):

Important
The threescale-wasm-auth module for integration with OpenShift Service Mesh is deprecated. It is no longer supported starting from Service Mesh 3. While it remains available in earlier versions, anticipate its future decommissioning and avoid relying on it for new deployments. For more details, see the unsupported add-on configurations in Service Mesh 3.

Reference:
Unsupported add-on configurations in Service Mesh 3