fix: expose ListFilesEntry (#19804)

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- This is a follow-up of #19573 

## Rationale for this change

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`ListFilesEntry` is part of the public `ListFilesCache` trait signature,
but it was defined inside the private list_files_cache module and was
not re-exported from `cache/mod.rs`. As a result, downstream crates
could not name the return type of `ListFilesCache::list_entries`, making
the public trait effectively unusable.

## What changes are included in this PR?

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Re-export ListFilesEntry from `datafusion_execution::cache`

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Existing tests.

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Fix the broken public API.

Author: lonless9

datafusion/execution/src/cache/mod.rs

@@ -24,6 +24,7 @@ mod list_files_cache;
 
 pub use file_metadata_cache::DefaultFilesMetadataCache;
 pub use list_files_cache::DefaultListFilesCache;
+pub use list_files_cache::ListFilesEntry;
 pub use list_files_cache::TableScopedPath;
 
 /// Base trait for cache implementations with common operations.