[flink] Fail fast validation for delete with write-only mode enabled

[ArnavBalyan]

• DeleteAction now checks CoreOptions.writeOnly() at the start of run.
• If 'write-only' = 'true', it throws a clear UnsupportedOperationException.
• avoids deep FileStoreCommitImpl manifest conflict errors.
• Added testDeleteActionWriteOnlyRejected to assert the new guard.
• Related to #6137

[ASiegeLion]

if I add ‘write-only = true‘’ to the with attribute of the paimon table, example : CREATE TABLE paimon.dw_liupeiyue.yydw_dm_entity_person_paimon_mini( hdidstring,attributestring,last_update_dtstring,proctime AS PROCTIME(), PRIMARY KEY(hdid) NOT ENFORCED ) COMMENT '' WITH ( 'bucket' = '64', 'snapshot.time-retained' = '24h', 'write-only' = 'true', 'metastore.partitioned-table' = 'true', 'consumer.expiration-time' = '3d' )

executor flink batch sql ： delete from paimon.dw_liupeiyue.yydw_dm_entity_person_paimon_mini where hdid = '10074379'

flink web ui show ：

so, delete from should be supported write-only=true mode