[Improvement] Fix AUTO handling in DorisUtils.java

### What would you like to be improved?

In catalogs/catalog-jdbc-doris/src/main/java/org/apache/gravitino/catalog/doris/utils/DorisUtils.java, checks for a missing bucket group, preventing errors when the BUCKETS clause is absent and defaulting to 1 or AUTO as appropriate.

Here's a test to help:
```
@Test
public void testDistributionWithoutBucketClauseDefaultsToOne() {
String createTableSql =
"CREATE TABLE `testTable` (\n" +
"`col1` date NOT NULL\n) ENGINE=OLAP\n PARTITION BY RANGE(`col1`)\n()\n DISTRIBUTED BY HASH(`col1` )";
Distribution distribution = DorisUtils.extractDistributionInfoFromSql(createTableSql);
assertEquals(distribution.number(), 1);
}
```

### How should we improve?

see above