Alias name not taking effect in a "over window" query with Beam SQL

The problem is that I don’t see the alias column “agg” in the query result's schema.

This is my code (with Beam 2.28):
```

Schema appSchema = Schema
.builder()
.addInt32Field("foo")

.addInt32Field("bar")
.build();

Row rowOne = Row.withSchema(appSchema).addValues(1,
1).build();
Row rowTwo = Row.withSchema(appSchema).addValues(1, 2).build();

PCollection
inputRows = pipeline
.apply(Create.of(rowOne, rowTwo))
.setRowSchema(appSchema);

String sql = "SELECT foo, bar, RANK() over (PARTITION BY foo ORDER BY bar) AS agg FROM PCOLLECTION";

PCollection result = inputRows.apply("sql", SqlTransform.query(sql));

```

The Beam schema of the query result is below. Row name is "w0$o0" instead of my specified name "agg".

Field{name=foo, description=, type=FieldType{typeName=INT32, nullable=false, logicalType=null, collectionElementType=null, mapKeyType=null, mapValueType=null, rowSchema=null, metadata={}}, options=``}
Field{name=bar, description=, type=FieldType{typeName=INT32, nullable=false, logicalType=null, collectionElementType=null, mapKeyType=null, mapValueType=null, rowSchema=null, metadata={}}, options=``}
Field{name=w0$o0, description=, type=FieldType{typeName=INT64, nullable=false, logicalType=null, collectionElementType=null, mapKeyType=null, mapValueType=null, rowSchema=null, metadata={}}, options=``}

Imported from Jira [BEAM-11930](https://issues.apache.org/jira/browse/BEAM-11930). Original Jira may contain additional context.
Reported by: sekiforever.