Fix unittest failures (pytorch#20009)

The Cmake build of image processor is failing, causing issues with
unittest.

The buck builds work. While I investigate the build failures, this turns
off image processor in our test jobs.

Author: metascroy

test/run_oss_cpp_tests.sh

@@ -47,7 +47,7 @@ build_executorch() {
     -DEXECUTORCH_BUILD_KERNELS_QUANTIZED=ON \
     -DEXECUTORCH_BUILD_EXTENSION_DATA_LOADER=ON \
     -DEXECUTORCH_BUILD_EXTENSION_FLAT_TENSOR=ON \
-    -DEXECUTORCH_BUILD_EXTENSION_IMAGE=ON \
+    -DEXECUTORCH_BUILD_EXTENSION_IMAGE=OFF \
     -DEXECUTORCH_BUILD_EXTENSION_MODULE=ON \
     -DEXECUTORCH_BUILD_EXTENSION_NAMED_DATA_MAP=ON \
     -DEXECUTORCH_BUILD_EXTENSION_LLM=ON \