cannon: Fix support for state version 7 in latest docker builds (#18311)

Latest cannon now only supports state version 8, so ensure we use an older cannon for state version 7 when building multicannon.

Author: ajsutton

cannon/Makefile

@@ -30,7 +30,6 @@ cannon64-impl:
 # Each embed is suffixed with the latest `StateVersion` number corresponding to the target VM and architecture.
 cannon-embeds: cannon64-impl
 	# 64-bit multithreaded vm
-	@cp bin/cannon64-impl ./multicannon/embeds/cannon-7
 	@cp bin/cannon64-impl ./multicannon/embeds/cannon-8
 
 cannon: cannon-embeds

ops/docker/op-stack-go/Dockerfile

@@ -102,6 +102,7 @@ FROM --platform=$BUILDPLATFORM us-docker.pkg.dev/oplabs-tools-artifacts/images/c
 FROM --platform=$BUILDPLATFORM us-docker.pkg.dev/oplabs-tools-artifacts/images/cannon:v1.2.0 AS cannon-builder-v1-2-0
 FROM --platform=$BUILDPLATFORM us-docker.pkg.dev/oplabs-tools-artifacts/images/cannon:v1.3.0 AS cannon-builder-v1-3-0
 FROM --platform=$BUILDPLATFORM us-docker.pkg.dev/oplabs-tools-artifacts/images/cannon:v1.4.0 AS cannon-builder-v1-4-0
+FROM --platform=$BUILDPLATFORM us-docker.pkg.dev/oplabs-tools-artifacts/images/cannon:v1.6.0 AS cannon-builder-v1-6-0
 
 FROM --platform=$BUILDPLATFORM builder AS cannon-builder
 ARG CANNON_VERSION=v0.0.0
@@ -113,6 +114,7 @@ COPY --from=cannon-builder-v1-2-0 /usr/local/bin/cannon-3 ./cannon/multicannon/e
 COPY --from=cannon-builder-v1-3-0 /usr/local/bin/cannon-4 ./cannon/multicannon/embeds/cannon-4
 COPY --from=cannon-builder-v1-4-0 /usr/local/bin/cannon-5 ./cannon/multicannon/embeds/cannon-5
 COPY --from=cannon-builder-v1-4-0 /usr/local/bin/cannon-6 ./cannon/multicannon/embeds/cannon-6
+COPY --from=cannon-builder-v1-6-0 /usr/local/bin/cannon-7 ./cannon/multicannon/embeds/cannon-7
 # Build current binaries
 RUN --mount=type=cache,target=/go/pkg/mod --mount=type=cache,target=/root/.cache/go-build cd cannon && make cannon  \
   GOOS=$TARGETOS GOARCH=$TARGETARCH GITCOMMIT=$GIT_COMMIT GITDATE=$GIT_DATE VERSION="$CANNON_VERSION"