fix: Correct extraneous parenthesis in GenerationConfig.toInternal

Removes an extra parenthesis and corrects the mapping logic within the `toInternal()` function in `GenerationConfig.kt` that was introduced when adding the `responseModalities` property.

Author: google-labs-jules[bot]

firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/type/GenerationConfig.kt

@@ -157,13 +157,9 @@ private constructor(
       stopSequences = stopSequences,
       frequencyPenalty = frequencyPenalty,
       presencePenalty = presencePenalty,
-        responseMimeType = responseMimeType,
-        responseSchema = responseSchema,
-        responseModalities = responseModalities,
-      )
       responseMimeType = responseMimeType,
       responseSchema = responseSchema?.toInternal(),
-      responseModalities = responseModalities?.map { it.toInternal() }
+      responseModalities = responseModalities?.map { it.toInternal() },
     )
 
   @Serializable