feat: remove staging layer in container build

This PR removes the staging layer.

spack.sh

@@ -25,6 +25,9 @@ d3bf1e04fca844abb7c1eeac38dda4e126c81b67
 8b2fec61f23a7b8230c0ed0378d90d04d8f590d8
 2242da65fdc06e7ac04c43613dc7795164b3a7a3
 1dc63dbea6c1d42aabf0e14b51439dcc46423e79
+3b59817ea7be35f4222dc88313734f7a30733ad7
+737b70cbbfacb3fba8054426e9b5bf8ede6d8faf
+a66586d749197841bd74e289802126f2359287a8
 ---
 ## Optional hash table with comma-separated file list
 read -r -d '' SPACK_CHERRYPICKS_FILES <<- \
@@ -49,3 +52,6 @@ read -r -d '' SPACK_CHERRYPICKS_FILES <<- \
 ## 8b2fec61f23a7b8230c0ed0378d90d04d8f590d8: hepmc3: add v3.3.0
 ## 2242da65fdc06e7ac04c43613dc7795164b3a7a3: graphviz: add through v12.1.0
 ## 1dc63dbea6c1d42aabf0e14b51439dcc46423e79: acts: add v34.1.0, v35.0.0 (identification, sycl variants changes)
+## 3b59817ea7be35f4222dc88313734f7a30733ad7: deal with TimeoutError from ssl.py
+## 737b70cbbfacb3fba8054426e9b5bf8ede6d8faf: Buildcache: remove deprecated --allow-root and preview subcommand
+## a66586d749197841bd74e289802126f2359287a8: spack buildcache push: best effort