Vertex AI: Should ImagenInlineImage#data be renamed ImagenInlineImage#bytesBase64Encoded ?

[thatfiredev]

The ImagenInlineImage#data is currently documented as:

firebase-android-sdk/firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/type/ImagenInlineImage.kt

Line 26 in 60a021d

* @param data Contains the raw bytes of the image

In reality, ImagenInlineImage#data contains the Base64 encoded image.

The Flutter and JS SDKs call it bytesBase64Encoded and their ref docs correctly mention the returned data is base64 encoded.
Renaming this field (data -> bytesBase64Encoded) would be a breaking change. But since Imagen support is in public preview, I think we should consider making the change when it goes GA.

For now, I think we should update the ref docs to point out the returned bytes are base64 encoded. I opened #6785 for that.

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It looks like the Swift SDK doesn't expose the base64 encoded image, it decodes it and returns as data: Data. I opened firebase/firebase-ios-sdk#14603 to discuss whether it should expose the base64 images