tests: use stable MAS integration in Synapse (#30473)

* tests: use stable MAS integration in Synapse

* Automatically follow MAS main branch

* Update the pinned Synapse container image to latest develop

* Update element-web-playwright-common to 1.4.5

* Fix the typing of the MAS config

* Update playwright-common to 1.4.6

* Use the modern MAS -> Synapse API

* Relax MAS rate limiting

* Revert using the modern API explicitly, it is now the default

* Better adjust the MAS rate limits

.github/workflows/playwright-image-updates.yaml

@@ -21,6 +21,15 @@ jobs:
               env:
                   IMAGE: ghcr.io/element-hq/synapse:develop
 
+            - name: Update MAS image
+              run: |
+                  docker pull "$IMAGE"
+                  INSPECT=$(docker inspect --format='{{index .RepoDigests 0}}' "$IMAGE")
+                  DIGEST=${INSPECT#*@}
+                  sed -i "s/const TAG.*/const TAG = \"main@$DIGEST\";/" playwright/testcontainers/mas.ts
+              env:
+                  IMAGE: ghcr.io/element-hq/matrix-authentication-service:main
+
             - name: Create Pull Request
               id: cpr
               uses: peter-evans/create-pull-request@271a8d0340265f705b14b6d32b9829c1cb33d45e # v7