[Bug]: Datastore's Read fails Pipeline validation and throws on DataflowRunner

### What happened?

Hello!

Sorry if this is a duplicate. To be honest, I don't know much about Apache Beam and Dataflow, so I am still learning and might be doing something wrong, let me know :)

I attempted to create a somewhat minimal example below. The exception is thrown by a pipeline that just reads an entry from Datastore when running on `DataflowRunner`. It works and succeeds when using `DirectRunner`.

The validation code was added in the PR #26675, throwing at [this line](https://github.com/apache/beam/blob/a434a31507895ecfef3be94bdc1729cf376ebf56/runners/core-construction-java/src/main/java/org/apache/beam/runners/core/construction/graph/PipelineValidator.java#L221).

Example code:
```java
private static Read buildQueryTransform(Options options, String kind, String column3Value) {
Query.Builder queryBuilder = Query.newBuilder();
queryBuilder.addKindBuilder().setName(kind);
queryBuilder.addProjection(makeProjection(COLUMN_NAME_1));
queryBuilder.addProjection(makeProjection(COLUMN_NAME_2));
queryBuilder.setFilter(makeFilter(COLUMN_NAME_3, Operator.EQUAL, makeValue(column3Value)));
Query query = queryBuilder.build();
return DatastoreIO.v1().read().withProjectId(options.getDataset()).withQuery(query);
}

private static Projection.Builder makeProjection(String propertyName) {
Projection.Builder prjBuilder = Projection.newBuilder();
prjBuilder.setProperty(makePropertyReference(propertyName));
return prjBuilder;
}

public static void main(String[] args) {
// ...

Pipeline pipeline = Pipeline.create(options);

// ...

Read reader = buildQueryTransform(options, sourceKind, value);
pipeline.apply("Read " + value + " from " + sourceKind, reader);

// ...

PipelineResult result = pipeline.run(); // throws IllegalArgumentException

// ...
}
```

Exception thrown:
```
SEVERE: Unexpected error in Dataflow job
java.lang.IllegalArgumentException: Transform Read-[column 3 value]-from-[datastore kind name]-Create-Values-Read-CreateSource--Impulse is not a composite transform but does not have a specified URN. outputs {
key: "org.apache.beam.sdk.values.PCollection.:397#bb20b45fd4d95138"
value: "Read [column 3 value] from [datastore kind name]/Create.Values/Read(CreateSource)/Impulse.out"
}
unique_name: "Read [column 3 value] from [datastore kind name]/Create.Values/Read(CreateSource)/Impulse"

at org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkArgument(Preconditions.java:440)
at org.apache.beam.runners.core.construction.graph.PipelineValidator.validateTransform(PipelineValidator.java:219)
at org.apache.beam.runners.core.construction.graph.PipelineValidator.validateComponents(PipelineValidator.java:121)
at org.apache.beam.runners.core.construction.graph.PipelineValidator.validate(PipelineValidator.java:101)
at org.apache.beam.runners.core.construction.PipelineTranslation.toProto(PipelineTranslation.java:106)
at org.apache.beam.runners.dataflow.DataflowRunner.run(DataflowRunner.java:1122)
at org.apache.beam.runners.dataflow.DataflowRunner.run(DataflowRunner.java:198)
at org.apache.beam.sdk.Pipeline.run(Pipeline.java:321)
at org.apache.beam.sdk.Pipeline.run(Pipeline.java:307)
at [our main class].main(MainDataflowJob.java:120)
```

Other log related to this unique name:
```xml

2023-08-16T13:56:55
1692205015473
278
org.apache.beam.sdk.runners.TransformHierarchy
FINE
org.apache.beam.sdk.runners.TransformHierarchy$Node
visit
1
Visiting primitive node Node{fullName=Read [column 3 value] from [datastore kind name]/Create.Values/Read(CreateSource)/Impulse, transform=Impulse}

2023-08-16T13:56:55
1692205015473
279
org.apache.beam.sdk.runners.TransformHierarchy
FINE
org.apache.beam.sdk.runners.TransformHierarchy$Node
visit
1
Visiting output value Read [column 3 value] from [datastore kind name]/Create.Values/Read(CreateSource)/Impulse.out [PCollection@1917161212]

```

### Issue Priority

Priority: 2 (default / most bugs should be filed as P2)

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