fix: revert amalthea upgrade from 0.20.0 to 0.19.2 (#4085)

Reverts a feature merged in release #4072

Author: olevski

helm-chart/renku/requirements.yaml

@@ -18,11 +18,11 @@ dependencies:
     condition: enableV1Services
   - name: amalthea
     repository: "https://swissdatasciencecenter.github.io/helm-charts/"
-    version: "0.20.0"
+    version: "0.19.2"
     condition: enableV1Services
   - name: amalthea-sessions
     repository: "https://swissdatasciencecenter.github.io/helm-charts/"
-    version: "0.20.0"
+    version: "0.19.2"
   - name: dlf-chart
     repository: "https://swissdatasciencecenter.github.io/datashim/"
     version: "0.3.9-renku-2"