Fix QNN Android Maven release build (pytorch#23234)

The QNN Maven publish for ExecuTorch 1.5.1 failed before AAR assembly
because the release workflow invokes `.ci/scripts/build-qnn-sdk.sh`.
That script builds the host-only `PyQnnManagerAdaptor` and
`quantized_ops_aot_lib`, which are not shipped in the Android artifact
and conflict with the newer PyTorch headers in the current CI image. The
failure is visible in [run
36488741446](https://github.com/pytorch/executorch/actions/runs/36488741446).

This removes that redundant host build. `setup-qnn-deps.sh` still
installs the QNN SDK, and `scripts/build_android_library.sh` still
builds the QNN runtime included in the AAR. Once merged, the workflow
can be dispatched with version `1.5.1`, source ref `v1.5.1`, flavor
`qnn`, and Maven upload enabled, so no new ExecuTorch version is
required.

Validation: YAML parsing, shell syntax checks for the invoked build
scripts, and `git diff --check`.

This PR was authored with Codex.

Author: JacobSzwejbka

.github/workflows/android-release-artifacts.yml

@@ -162,7 +162,8 @@ jobs:
 
         if [[ "$FLAVOR" == "qnn" || "$FLAVOR" == "all" ]]; then
           PYTHON_EXECUTABLE=python bash .ci/scripts/setup-qnn-deps.sh
-          PYTHON_EXECUTABLE=python bash .ci/scripts/build-qnn-sdk.sh
+          # build_android_library.sh builds the QNN runtime included in the AAR;
+          # the host-only PyQnnManagerAdaptor is not part of this artifact.
           export EXECUTORCH_BUILD_QNN=ON
           source backends/qualcomm/scripts/qnn_config.sh
           export QNN_SDK_ROOT="/tmp/qnn/${QNN_VERSION}"