Add support for URL input to Runtime Image

Currently, running a generative search with an image input doesn't support URLs as in input parameter...

i.e

response = await myCollection.generate.nearText("Movies", {
  groupedTask: {
    prompt: "Which movie is closest to the image in terms of atmosphere",
    images: [base64String],      // A list of base64 encoded strings of the image bytes
    // imageProperties: ["img"], // Properties containing images in Weaviate
}
  config: generativeParameters.anthropic({
    maxTokens: 1000
  }),
}, {
  limit: 5,
})

Could we support having a list of URLs as an input.

Start by tracing how Runtime Image inputs are handled for generative search in the TypeScript client, using the example in the issue as the expected entry point. Determine how the existing base64 image input is represented, then verify that a list of image URLs is accepted alongside it and behaves as requested.