[build] Expand Ubuntu disk cleanup and add pre-build space checks in CI

[AutomatedTester]

Summary

• Expand the Ubuntu disk space cleanup step to remove Android SDK (~15GB), Google Cloud SDK (~3GB), CodeQL (~5GB), and Docker images (~10–20GB). Together with the existing removals (GHC, Boost, Swift, Julia) this frees an additional ~33–43GB before the build starts. Docker image removal is safe: no CI workflow uses Docker services or containers.
• Add a "Disk usage after cache restore" step (df -h /) immediately after both setup-bazel variants so we can see how much the Bazel repository cache (currently ~3.5GB compressed) costs after extraction — the biggest single disk spike in any job.
• Add a "Check disk space before build" step on Ubuntu that hard-fails with a clear error message if less than 10GB is available. This catches disk exhaustion before Run Bazel starts, replacing a cryptic mid-build OOM with a named, actionable failure.

Motivation

Investigated a CI failure where disk space was identified as a risk. The existing cleanup only freed ~5–10GB and the end-of-job 5GB check fires too late to give a useful error. These changes add headroom and visibility at the points that matter.

Note: the threshold on the end-of-job check (currently 5GB) is left unchanged here — that change is under separate consideration.