ci: Remove unused package

Address feedback from https://github.com/bitcoin/bitcoin/pull/24561/files#r985719812

Author: MacroFake

ci/test/00_setup_env_i686_multiprocess.sh

@@ -9,7 +9,7 @@ export LC_ALL=C.UTF-8
 export HOST=i686-pc-linux-gnu
 export CONTAINER_NAME=ci_i686_multiprocess
 export DOCKER_NAME_TAG=ubuntu:20.04
-export PACKAGES="cmake python3 python3-pip llvm clang g++-multilib"
+export PACKAGES="cmake python3 llvm clang g++-multilib"
 export DEP_OPTS="DEBUG=1 MULTIPROCESS=1"
 export GOAL="install"
 export BITCOIN_CONFIG="--enable-debug CC='clang -m32' CXX='clang++ -m32' LDFLAGS='--rtlib=compiler-rt -lgcc_s'"