[Bug]: DualInputNestedValueProvider is not able to get Value properly if input is RuntimeValueProvider.

### What happened?

Background:
DualInputNestedValueProvider
https://github.com/GoogleCloudPlatform/DataflowTemplates/blob/c7cb59f37766b7edfd0eb14f6f184f7c13b7909b/v1/src/main/java/com/google/cloud/teleport/util/DualInputNestedValueProvider.java#L29 is not in Apache Beam package. However, it uses ValueProvider from SDK.

The issue:
If one of the input for DualInputNestedValueProvider is RuntimeValueProvider, then the input will still be a ValueProvider in input.getX() or input.getY() while we're expecting the real value of the ValueProvider should be fetched by the call.

### Issue Priority

Priority: 3 (minor)

### Issue Components

- [ ] Component: Python SDK
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