[ML] Use python:3 instead of python:3-slim for analyze_build_failure step

Same fix as #3000 — python:3-slim lacks curl and git needed by the
Buildkite agent environment hook.

Made-with: Cursor

Author: edsavage

.buildkite/pipelines/analyze_build_failure.yml.sh

@@ -23,5 +23,5 @@ steps:
     if: "build.state == 'failed' || build.state == 'failing'"
     soft_fail: true
     agents:
-      image: "python:3-slim"
+      image: "python:3"
 EOL