Exception when using DELETE FROM Spark query on table using copy-on-write

### Apache Iceberg version

1.10.0 (latest release)

### Query engine

Spark

### Please describe the bug 🐞

We are using a Spark job to remove expired rows from an Iceberg table based on a unix timestamp column (stored as an integer).

The query is

DELETE FROM $table
WHERE status = 'Deleted'
AND deleted_date < $timestamp

This works correctly when the table has `'write.delete.mode' = 'merge-on-read'`.

However with the table in `copy-on-write` mode, the query fails with an `IllegalStateException` in the last stage of the deletion to rewrite data:

```
java.lang.IllegalStateException: Not an instance of java.lang.CharSequence: 4829
at org.apache.iceberg.data.GenericRecord.get(GenericRecord.java:138)
at org.apache.iceberg.data.InternalRecordWrapper.get(InternalRecordWrapper.java:101)
at org.apache.iceberg.types.Comparators$StructLikeComparator.compare(Comparators.java:121)
at org.apache.iceberg.types.Comparators$StructLikeComparator.compare(Comparators.java:94)
at org.apache.iceberg.util.StructLikeWrapper.equals(StructLikeWrapper.java:91)
at java.base/java.util.HashMap.putVal(HashMap.java:644)
at java.base/java.util.HashMap.put(HashMap.java:608)
at java.base/java.util.HashSet.add(HashSet.java:220)
at org.apache.iceberg.util.StructLikeSet.add(StructLikeSet.java:102)
at org.apache.iceberg.util.StructLikeSet.add(StructLikeSet.java:32)
at org.apache.iceberg.relocated.com.google.common.collect.Iterators.addAll(Iterators.java:370)
at org.apache.iceberg.relocated.com.google.common.collect.Iterables.addAll(Iterables.java:332)
at org.apache.iceberg.data.BaseDeleteLoader.loadEqualityDeletes(BaseDeleteLoader.java:115)
at org.apache.iceberg.data.DeleteFilter.applyEqDeletes(DeleteFilter.java:207)
at org.apache.iceberg.data.DeleteFilter.applyEqDeletes(DeleteFilter.java:224)
at org.apache.iceberg.data.DeleteFilter.filter(DeleteFilter.java:178)
at org.apache.iceberg.spark.source.RowDataReader.open(RowDataReader.java:99)
at org.apache.iceberg.spark.source.RowDataReader.open(RowDataReader.java:43)
at org.apache.iceberg.spark.source.BaseReader.next(BaseReader.java:141)
at org.apache.spark.sql.execution.datasources.v2.PartitionIterator.hasNext(DataSourceRDD.scala:120)
at org.apache.spark.sql.execution.datasources.v2.MetricsIterator.hasNext(DataSourceRDD.scala:158)
at org.apache.spark.sql.execution.datasources.v2.DataSourceRDD$$anon$1.$anonfun$hasNext$1(DataSourceRDD.scala:63)
at org.apache.spark.sql.execution.datasources.v2.DataSourceRDD$$anon$1.$anonfun$hasNext$1$adapted(DataSourceRDD.scala:63)
at scala.Option.exists(Option.scala:376)
at org.apache.spark.sql.execution.datasources.v2.DataSourceRDD$$anon$1.hasNext(DataSourceRDD.scala:63)
at org.apache.spark.sql.execution.datasources.v2.DataSourceRDD$$anon$1.advanceToNextIter(DataSourceRDD.scala:97)
at org.apache.spark.sql.execution.datasources.v2.DataSourceRDD$$anon$1.hasNext(DataSourceRDD.scala:63)
at org.apache.spark.InterruptibleIterator.hasNext(InterruptibleIterator.scala:37)
at scala.collection.Iterator$$anon$10.hasNext(Iterator.scala:460)
at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage1.processNext(Unknown Source)
at org.apache.spark.sql.execution.BufferedRowIterator.hasNext(BufferedRowIterator.java:43)
at org.apache.spark.sql.execution.WholeStageCodegenEvaluatorFactory$WholeStageCodegenPartitionEvaluator$$anon$1.hasNext(WholeStageCodegenEvaluatorFactory.scala:43)
at scala.collection.Iterator$$anon$10.hasNext(Iterator.scala:460)
at org.apache.spark.shuffle.sort.BypassMergeSortShuffleWriter.write(BypassMergeSortShuffleWriter.java:140)
at org.apache.spark.shuffle.ShuffleWriteProcessor.write(ShuffleWriteProcessor.scala:59)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:104)
at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:54)
at org.apache.spark.TaskContext.runTaskWithListeners(TaskContext.scala:166)
at org.apache.spark.scheduler.Task.run(Task.scala:141)
at org.apache.spark.executor.Executor$TaskRunner.$anonfun$run$4(Executor.scala:620)
at org.apache.spark.util.SparkErrorUtils.tryWithSafeFinally(SparkErrorUtils.scala:64)
at org.apache.spark.util.SparkErrorUtils.tryWithSafeFinally$(SparkErrorUtils.scala:61)
at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:94)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:623)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:829)
```

### Willingness to contribute

- [ ] I can contribute a fix for this bug independently
- [x] I would be willing to contribute a fix for this bug with guidance from the Iceberg community
- [ ] I cannot contribute a fix for this bug at this time