Use schema instead of parameters

This is a remnant of previous renaming work.

Author: rlazo

firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/internal/util/conversions.kt

@@ -153,7 +153,7 @@ internal fun Tool.toInternal() =
   com.google.firebase.vertexai.common.client.Tool(functionDeclarations.map { it.toInternal() })
 
 internal fun FunctionDeclaration.toInternal() =
-  com.google.firebase.vertexai.common.client.FunctionDeclaration(name, "", parameters.toInternal())
+  com.google.firebase.vertexai.common.client.FunctionDeclaration(name, "", schema.toInternal())
 
 internal fun com.google.firebase.vertexai.type.Schema.toInternal(): Schema =
   Schema(

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

@@ -42,6 +42,6 @@ class FunctionDeclaration(
   val parameters: Map<String, Schema>,
   val optionalParameters: List<String> = emptyList(),
 ) {
-  private val schema: Schema =
+  internal val schema: Schema =
     Schema.obj(properties = parameters, optionalProperties = optionalParameters, nullable = false)
 }