GHA: drop 3rd-party apt source docker.list

Seen on `ubuntu-slim` runners.

Also:
- extend to two jobs to `ls -l` package sources on both ubuntu-latest,
  ubuntu-24.04-arm, and ubuntu-slim.
- drop former stray apt source `ondrej-ubuntu-php-noble.sources`.
  It's no longer present on the image.

Closes #21344

.github/workflows/linux.yml

@@ -454,7 +454,8 @@ jobs:
             ${{ contains(matrix.build.install_steps, 'pytest') && 'apache2 apache2-dev libnghttp2-dev vsftpd dante-server' || '' }}
 
         run: |
-          sudo rm -f /etc/apt/sources.list.d/{azure-cli.sources,microsoft-prod.list,ondrej-ubuntu-php-noble.sources}
+          ls -l /etc/apt/sources.list.d
+          sudo rm -f /etc/apt/sources.list.d/{azure-cli.sources,docker.list,microsoft-prod.list}
           sudo apt-get -o Dpkg::Use-Pty=0 update
           printf "#!/bin/sh
             while [ \$? = 0 ]; do for i in 1 2 3; do timeout 45 \"\$@\" && break 2; echo \"Error: slow server, retry \$i\"; sleep 1
@@ -477,7 +478,7 @@ jobs:
       - name: 'install prereqs (i686)'
         if: ${{ contains(matrix.build.name, 'i686') }}
         run: |
-          sudo rm -f /etc/apt/sources.list.d/{azure-cli.sources,microsoft-prod.list,ondrej-ubuntu-php-noble.sources}
+          sudo rm -f /etc/apt/sources.list.d/{azure-cli.sources,docker.list,microsoft-prod.list}
           sudo dpkg --add-architecture i386
           sudo apt-get -o Dpkg::Use-Pty=0 update
           printf "#!/bin/sh