minor: diagnostics when MSQ's on-demand segment cache can't fit an input segment

[cecemei]

Description

MSQ workers read input segments through a virtual-storage cache (SegmentLocalCacheManager/StorageLocation) sized as a fraction of tmpStorageBytesPerTask. If a single segment exceeds that cache's capacity, it fails unconditionally (nothing can be evicted to make room), and the resulting error gives no numbers, just "ensure enough disk space has been allocated." The actual size/capacity data was already computed for a debug log line but never surfaced. This PR is diagnostics-only, no behavior change.

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This PR has:

• been self-reviewed.
  • using the concurrency checklist (Remove this item if the PR doesn't have any relation to concurrency.)
• added documentation for new or modified features or behaviors.
• a release note entry in the PR description.
• added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
• added or updated version, license, or notice information in licenses.yaml
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
• added integration tests.
• been tested in a test Druid cluster.