Fix playwright-screenshots utility for native dependencies

Without this, a developer would need to both specify --with-node-modules && --entrypoint and provide a custom entrypoint to do the `yarn install`.

packages/element-web-playwright-common/Dockerfile

@@ -6,4 +6,6 @@ WORKDIR /work
 # fonts-dejavu is needed for the same RTL rendering as on CI
 RUN apt-get update && apt-get -y install docker.io fonts-dejavu
 
-ENTRYPOINT ["npx", "playwright", "test", "--update-snapshots", "--reporter", "line"]
+COPY docker-entrypoint.sh /docker-entrypoint.sh
+
+ENTRYPOINT ["docker-entrypoint.sh"]

packages/element-web-playwright-common/docker-entrypoint.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+
+set -e
+
+if [[ "$YARN_INSTALL" == "true" ]]; then
+  yarn install --frozen-lockfile
+fi
+
+npx playwright test --update-snapshots --reporter line "$@"

packages/element-web-playwright-common/playwright-screenshots.sh

@@ -59,7 +59,7 @@ while [[ $# -gt 0 ]]; do
     # It's a volume rather than a directory because otherwise things tend to start picking up
     # files from it in the native environment and break.
     --with-node-modules)
-      RUN_ARGS+=(--mount "type=volume,src=ew-docker-node-modules,dst=/work/node_modules,volume-nocopy")
+      RUN_ARGS+=(--mount "type=volume,src=ew-docker-node-modules,dst=/work/node_modules,volume-nocopy" -e YARN_INSTALL=true)
       shift
       ;;
     # Sets a different entrypoint (in which case the default arguments to the script will be ignored)