[Buildkite] Remove i686-linux-android from rustup target add

Summary: This should have been removed as part of D8689

Test Plan: NA, see if this passes

Reviewers: ashoat, ginsu, marcin, tomek, jon

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D8701

.buildkite/android.yml

@@ -3,7 +3,7 @@ steps:
     command:
       - 'curl https://sh.rustup.rs -sSf | sh -s -- -y'
       - 'source /root/.cargo/env'
-      - 'rustup target add aarch64-linux-android arm-linux-androideabi i686-linux-android x86_64-linux-android'
+      - 'rustup target add aarch64-linux-android arm-linux-androideabi x86_64-linux-android'
       - 'apt update && apt install -y autoconf libtool build-essential cmake git libgtest-dev libssl-dev zlib1g-dev'
       - 'scripts/install_protobuf.sh'
       - 'yarn ci-cleaninstall'