[DO NOT MERGE] ci: Use a new volume for depends sources cache

This is required to workaround the cache contaminated by unversioned
files in the early versions of this branch.

Can be dropped after cleaning the cache in the Cirrus CI infra.

Suggested in bitcoin#30997 (comment)

ci/test/02_run_container.sh

@@ -37,12 +37,12 @@ if [ -z "$DANGER_RUN_CI_ON_HOST" ]; then
 
   docker volume create "${CONTAINER_NAME}_ccache" || true
   docker volume create "${CONTAINER_NAME}_depends" || true
-  docker volume create "${CONTAINER_NAME}_depends_sources" || true
+  docker volume create "pr30997_${CONTAINER_NAME}_depends_sources" || true
   docker volume create "${CONTAINER_NAME}_previous_releases" || true
 
   CI_CCACHE_MOUNT="type=volume,src=${CONTAINER_NAME}_ccache,dst=$CCACHE_DIR"
   CI_DEPENDS_MOUNT="type=volume,src=${CONTAINER_NAME}_depends,dst=$DEPENDS_DIR/built"
-  CI_DEPENDS_SOURCES_MOUNT="type=volume,src=${CONTAINER_NAME}_depends_sources,dst=$DEPENDS_DIR/sources"
+  CI_DEPENDS_SOURCES_MOUNT="type=volume,src=pr30997_${CONTAINER_NAME}_depends_sources,dst=$DEPENDS_DIR/sources"
   CI_PREVIOUS_RELEASES_MOUNT="type=volume,src=${CONTAINER_NAME}_previous_releases,dst=$PREVIOUS_RELEASES_DIR"
 
   if [ "$DANGER_CI_ON_HOST_CACHE_FOLDERS" ]; then