Annotate output from playwright-screenshots scripts (#33176)

... to make it easier to see where it is coming from

Also, add a blank line before starting playwright itself

packages/playwright-common/playwright-screenshots.sh

@@ -9,7 +9,7 @@ SCRIPT_DIR=$(dirname "$SCRIPT_PATH")
 function build_image() {
     local IMAGE_NAME="$1"
 
-    echo "Building $IMAGE_NAME image in $SCRIPT_DIR"
+    echo "playwright-screenshots: Building $IMAGE_NAME image in $SCRIPT_DIR"
     docker build -t "$IMAGE_NAME" --build-arg "PLAYWRIGHT_VERSION=${IMAGE_NAME#*:}" "$SCRIPT_DIR"
 }
 
@@ -34,16 +34,19 @@ CONTAINER=$(docker run --network=host -v /tmp:/tmp --rm -d -e PORT="$WS_PORT" "$
 # Set up an exit trap to clean up the docker container
 clean_up() {
     ARG=$?
-    echo "Stopping playwright-server"
+    echo "playwright-screenshots: Stopping playwright-server"
     docker stop "$CONTAINER" > /dev/null
     exit $ARG
 }
 trap clean_up EXIT
 
 # Wait for playwright-server to be ready
-echo "Waiting for playwright-server"
+echo "playwright-screenshots: Waiting for playwright-server"
 pnpm --dir "$SCRIPT_DIR" exec wait-on "tcp:$WS_PORT"
 
+# Playwright seems to overwrite the last line from the console, so add an
+# extra newline to make sure this doesn't get lost.
+echo -e "playwright-screenshots: Running '$@'\n"
+
 # Run the test we were given, setting PW_TEST_CONNECT_WS_ENDPOINT accordingly
-echo "Running '$@'"
 PW_TEST_CONNECT_WS_ENDPOINT="http://localhost:$WS_PORT" "$@"