[Hotfix] Meet NPE when loading tables which use s3 storage

[tcodehuber]

Why are the changes needed?

Using ams internal catalog and s3 as storage, but NPE occurs. The root cause is that org.apache.amoro.server.utils.InternalTableUtil#newIcebergFileIo L86 -> Configuration conf = store.getConfiguration();

core-site and hdfs-site is null when using s3 storage.

Brief change log

How was this patch tested?

• [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible

• [ ] Add screenshots for manual tests if appropriate

• [ ] Run test locally before making a pull request

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)