Stop installing the withdrawn Android SDK 'tools' package (#22917)

## Problem

Any commit touching `.ci/docker` changes the CI image tag — it is
literally
`git rev-parse HEAD:.ci/docker` (`_docker-image.yml`) — and the
resulting rebuild runs
`install_android.sh`, which now dies:

```
+ /opt/cmdline-tools/bin/sdkmanager --sdk_root=/opt/android/sdk --install tools
Warning: Failed to find package 'tools'
```

Google has withdrawn the obsolete `tools` package. The script already
skipped it on aarch64, where
it disappeared first:

```bash
# The 'tools' package (emulator) is not available on aarch64
if [ "$(uname -m)" != "aarch64" ]; then
```

It is now gone for every host, so `sdkmanager` exits non-zero and `set
-e` takes the image build
down with it.

## Why it matters beyond one PR

`_docker-image.yml` notes that nothing waits for `docker-builds`, and
that without the images
"the pod fails to pull and the job has to be re-run once they land". So
a `.ci/docker` change that
merges while its image build is red leaves main pointing at tags that
were never published, and the
jobs using those images fail to start. Today that is
`executorch-ubuntu-22.04-clang12-android` and
`executorch-ubuntu-22.04-mediatek-sdk`.

## Fix

Drop the `tools` install. Its replacements, `cmdline-tools` and
`platform-tools`, are installed
directly above. The old comment described it as "tools for future
emulator tests", but the emulator
ships as its own package and nothing in CI installs or runs one, so this
loses no capability.

## How this came up

Found while trying to land the PyTorch pin bump in #22793. That PR edits
`.ci/docker/ci_commit_pins/pytorch.txt`, so it forces an image rebuild
and is the first change in a
while to actually execute this line — its `docker-build` jobs fail here,
not on anything to do with
the pin. Split out because the two are unrelated and this unblocks every
future `.ci/docker` change.

**Sequencing:** this needs to land before #22793, which then wants a
rebase to pick it up.

Carries `ciflow/docker` so the images are actually built and this
validates itself.

cc @digantdesai @jakeszwe

---

Authored with Claude Code.

---------

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: psiddh

.ci/docker/common/install_android.sh

@@ -79,10 +79,9 @@ install_sdk() {
   yes | /opt/cmdline-tools/bin/sdkmanager --sdk_root="${SDK_INSTALLATION_DIR}" --install "build-tools;35.0.0"
   # And some more tools for future emulator tests
   yes | /opt/cmdline-tools/bin/sdkmanager --sdk_root="${SDK_INSTALLATION_DIR}" --install "platform-tools"
-  # The 'tools' package (emulator) is not available on aarch64
-  if [ "$(uname -m)" != "aarch64" ]; then
-    yes | /opt/cmdline-tools/bin/sdkmanager --sdk_root="${SDK_INSTALLATION_DIR}" --install "tools"
-  fi
+  # Google withdrew the 'tools' package, so installing it fails under set -e.
+  # cmdline-tools and platform-tools above replace it, and this image neither
+  # installs nor runs an emulator.
 }
 
 install_prerequiresites