Update pnpm (#34066)

apps/desktop/dockerbuild/Dockerfile

@@ -1,10 +1,17 @@
+# syntax=docker.io/docker/dockerfile:1.25-labs@sha256:4426b5e269e36911b94fb79cf67f1fd7155ef11b2bbc8ab23cbfcbc97130efe9
 # Docker image to facilitate building Element Desktop's native bits using a glibc version (2.31)
 # with broader compatibility, down to Debian bullseye & Ubuntu focal.
 
+# PNPM source
+FROM --platform=$BUILDPLATFORM ghcr.io/pnpm/pnpm:11.10.0@sha256:9a6eb06d5f861d830fe27d85a91415e60527fa45ec45b52ee43c92a8aaf3bf8a AS pnpm
+
 FROM rust:bullseye@sha256:21d112adb6ab370d39eef8f861f10b42342419b9569e7a05dac15e19eb65a3b4
 
 ENV DEBIAN_FRONTEND=noninteractive
 
+COPY --from=pnpm /opt/pnpm /opt/pnpm
+RUN ln -s /opt/pnpm/pnpm /usr/local/bin/pnpm
+
 RUN apt-get -qq update && apt-get -y -qq dist-upgrade && \
   apt-get -y -qq install --no-install-recommends \
   # tclsh is required for building SQLite as part of SQLCipher

apps/desktop/dockerbuild/setup.sh

@@ -9,4 +9,5 @@ ARCH="${archMap["$TARGETARCH"]}"
 NODE_VERSION=$(cat /.node-version | sed -e 's/^v//')
 curl --proto "=https" -L "https://nodejs.org/dist/v$NODE_VERSION/node-v$NODE_VERSION-$TARGETOS-$ARCH.tar.gz" | tar xz -C /usr/local --strip-components=1 && \
   unlink /usr/local/CHANGELOG.md && unlink /usr/local/LICENSE && unlink /usr/local/README.md
-corepack enable
+# We need yarn classic to build seshat
+npm install --global yarn@1