ci(build): scope Docker layer cache per artifact to avoid cross-contamination (#5453)

This pull request updates the Docker build caching strategy in the
GitHub Actions workflow to improve cache isolation and efficiency. The
main change is the introduction of a cache `scope` based on the
`artifact-suffix` matrix value.

**Build caching improvements:**

*
[`.github/workflows/build.yml`](diffhunk://#diff-5c3fa597431eda03ac3339ae6bf7f05e1a50d6fc7333679ec38e21b337cb6721L329-R330):
Updated `cache-from` and `cache-to` in the Docker build step to use a
scoped cache (`scope=${{ matrix.artifact-suffix }}`), enabling better
cache isolation across different build variants.

.github/workflows/build.yml

@@ -326,8 +326,8 @@ jobs:
           context: .
           file: ./${{ matrix.docker-rev }}
           push: false
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-from: type=gha,scope=${{ matrix.artifact-suffix }}
+          cache-to: type=gha,mode=max,scope=${{ matrix.artifact-suffix }}
           platforms: linux/amd64,linux/arm64/v8
           provenance: true
           sbom: true