[BUG] Log GC offset should be one above minimum compaction offset (#4938)

## Description of changes

_Summarize the changes made by this PR._

- Improvements & Bug fixes
  - Adjust the minimum log offset to keep. Previously it is the minimum compaction offset (i.e. the last log offset that has been compacted) across all kept collection versions, and now it is one more than this.
- New functionality
  - N/A

## Test plan

_How are these changes tested?_

- [ ] Tests pass locally with `pytest` for python, `yarn test` for js, `cargo test` for rust

## Documentation Changes

_Are all docstrings for user-facing APIs updated if required? Do we need to make documentation changes in the [docs section](https://github.com/chroma-core/chroma/tree/main/docs/docs.trychroma.com)?_

Author: Sicheng-Pan

rust/garbage_collector/src/garbage_collector_orchestrator_v2.rs

@@ -479,7 +479,7 @@ impl GarbageCollectorOrchestrator {
                     "Expected version file to contain version history".to_string(),
                 ))?
                 .versions;
-            let min_log_offset = version_history
+            let min_compaction_log_offset = version_history
                 .iter()
                 .find(|version_info| version_info.version == min_version_to_keep)
                 .ok_or(GarbageCollectorError::InvariantViolation(
@@ -497,8 +497,11 @@ impl GarbageCollectorOrchestrator {
                         "Expected log offset to be unsigned".to_string(),
                     )
                 })?;
-            collections_to_garbage_collect
-                .insert(*collection_id, LogPosition::from_offset(min_log_offset));
+            collections_to_garbage_collect.insert(
+                *collection_id,
+                // The minimum offset to keep is one after the minimum compaction offset
+                LogPosition::from_offset(min_compaction_log_offset) + 1u64,
+            );
         }
 
         let task = wrap(