mobile: Force mobile-release-common build to use C++17

It was defaulting to C++20 due to
envoyproxy#32585, but for mobile, we are
still on C++17. This change enables local builds to build with C++17
without encountering toolchain errors.

Signed-off-by: Ali Beyad <abeyad@google.com>

mobile/.bazelrc

@@ -131,6 +131,9 @@ build:mobile-remote-release-clang-android-publish --linkopt=-fuse-ld=lld
 build:mobile-remote-release-clang-android-publish-xds --config=mobile-remote-release-clang-android-publish
 build:mobile-remote-release-clang-android-publish-xds --define=envoy_mobile_xds=enabled
 
+# Temporary revert to C++17 for mobile NDK builds.
+build:mobile-release-common --cxxopt=-std=c++17 --host_cxxopt=-std=c++17
+
 # Compile releases optimizing for size (eg -Os, etc).
 build:mobile-release-common --config=sizeopt