Fix breakage when extracting "data" as the path in GraphQLResponse

Recently a change was made in b386856 that broke support for extracting
the value from the response using the path "data". While users could simply
use the "dataAsObject" method, there are many instances where users call
extractValue with "data" as the path. Restore support for this, and add
unit tests.

(cherry picked from commit 163d1bc)

graphql-dgs-client/src/main/kotlin/com/netflix/graphql/dgs/client/GraphQLResponse.kt

@@ -131,7 +131,11 @@ data class GraphQLResponse(val json: String, val headers: Map<String, List<Strin
             .addOptions(Option.DEFAULT_PATH_LEAF_TO_NULL)
 
         fun getDataPath(path: String): String {
-            return if (!path.startsWith("data.")) "data.$path" else path
+            return if (path == "data" || path.startsWith("data.")) {
+                path
+            } else {
+                "data.$path"
+            }
         }
     }
 }

graphql-dgs-client/src/test/kotlin/com/netflix/graphql/dgs/client/GraphQLResponseTest.kt

@@ -19,6 +19,7 @@
 package com.netflix.graphql.dgs.client
 
 import org.assertj.core.api.Assertions.assertThat
+import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.params.ParameterizedTest
 import org.junit.jupiter.params.provider.CsvSource
@@ -53,6 +54,7 @@ class GraphQLResponseTest {
     @ParameterizedTest
     @CsvSource(
         value = [
+            "data, data",
             "foo, data.foo",
             "data.foo, data.foo",
             "datafoo, data.datafoo"
@@ -238,4 +240,21 @@ class GraphQLResponseTest {
 
         server.verify()
     }
+
+    @Test
+    fun testExtractValue() {
+        val response = GraphQLResponse("""{"data": {"submitReview": {"submittedBy": "[email protected]"}}}""")
+        val result = response.extractValue<Map<String, Any?>>("data")
+        assertEquals(mapOf("submitReview" to mapOf("submittedBy" to "[email protected]")), result)
+        assertEquals("[email protected]", response.extractValue("data.submitReview.submittedBy"))
+        assertEquals("[email protected]", response.extractValue("submitReview.submittedBy"))
+    }
+
+    @Test
+    fun testDataAsObject() {
+        data class Response(val submitReview: Map<String, String>)
+        val response = GraphQLResponse("""{"data": {"submitReview": {"submittedBy": "[email protected]"}}}""")
+        val result = response.dataAsObject(Response::class.java)
+        assertEquals(Response(submitReview = mapOf("submittedBy" to "[email protected]")), result)
+    }
 }