Incremental clean planning should ignore partitions from instants with only new file groups

### Task Description

**What needs to be done:**
Currently when incremental clean planner scans all instants since latest earliest commit to retain (ECTR), `org.apache.hudi.table.action.clean.CleanPlanner#getPartitionsForInstants` will add all partitions across all instants' `partitionToWriteStats`. We should optimize this flow such that when processing `commit` instants we only add a partition if the `commit` metadata has any entry in `partitionToWriteStats` where a file group was updated. If any instant updated/replaced a file group, we should still add it to list of partitions to scan (so that we don't "miss" any files to clean).

**Why this task is needed:*
For insert-only workloads (where small file handling is disabled), if there are thousands of partitions touched by `commit`s since the latest ECTR, then clean planner will have to unnecessarily scan all of these partitions (even though there is nothing to clean in these partitions).

### Task Type

Performance optimization

### Related Issues

**Parent feature issue:** (if applicable )
**Related issues:**
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Start in org.apache.hudi.table.action.clean.CleanPlanner#getPartitionsForInstants and trace how commit metadata populates partitionToWriteStats. Verify the planner distinguishes commits with only new file groups from instants that updated or replaced file groups, while still scanning every partition that may contain files to clean.

Written by the indexing model from the issue text.