output_files can be very noisy, drop from debug

[palfrey]

Description

We've been seeing logs like

2026-01-26T16:49:21.550606027Z {"timestamp":"2026-01-26T16:49:21.539381Z","level":"INFO","fields":{"return":"Response { metadata: MetadataMap { headers: {} }, message: ActionResult { output_files: [OutputFile { path: \"bazel-out/k8-opt/bin/external/local_config_cuda/cuda/cuda/include/CL/cl.h\", digest: Some(Digest { hash: \"ac6c0342b43ac65dea712fce8db8ea6e0abbbbf7e0ca6e2bd5390dd25bc790bf\", size_bytes: 62740 }), is_executable: true, contents: b\"\", node_properties: None }, OutputFile { path: \"bazel-out/k8-opt/bin/external/local_config_cuda/cuda/cuda/include/CL/cl.hpp\", digest: Some(Digest { hash: \"965b10881acb8389f7da49f07be63c22a7c449c9dd964427831768d267065ac9\", size_bytes: 298441 }), is_executable: true, contents: b\"\", node_properties: None }, OutputFile { path: \"bazel-out/k8-opt/bin/external/local_config_cuda/cuda/cuda/include/CL/cl_egl.h\", digest: Some(Digest { hash: \"31e046f50c34b24ddb9dd2a9eb182c854703c862c5e10f0145175567d6b6e670\", size_bytes: 5164 }), is_executable: true, contents: b\"\", node_properties: None }, OutputFile { path: \"bazel-out/k8-opt/bin/external/local_config_cuda/cuda/cuda/include/CL/cl_ext.h\", digest: Some(Digest { hash: \"c22b00295c73b58011c1ac7b9ec9aed7ac4ea5fef970c874efe8b62d7702f953\", size_bytes: 16107 }), is_executable: true, contents: b\"\", node_properties: None }, OutputFile { path: \"bazel-out/k8-opt/bin/external/local_config_cuda/cuda/cuda/include/CL/cl_gl.h\", digest: Some(Digest { hash: \"0b53a3b04bbcd6c122acc0fe9ccdacf80d521a64bb29c02cddad60a4ea447bf8\", size_bytes: 7346 }), is_executable: true, contents: b\"\", node_properties: None }, OutputFile { path: \"bazel-out/k8-opt/bin/external/local_config_cuda/cuda/cuda/include/CL/cl_gl_ext.h

(continue for many, many pages)

It's noisy, it swamps other logs, it's not very useful. This PR drops output_files from the debug output.

Type of change

Please delete options that aren't relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

bazel test //...

Checklist

• Updated documentation if needed
• Tests added/amended
• bazel test //... passes locally
• PR is contained in a single commit, using git amend see some docs

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This change is