Add missing default dictionary field in privacy manifest

Summary:
I was getting some feedback from one of my libraries that the privacy manifest was reporting validation errors, and when I checked the privacy manifest here, it was similarly incorrectly structured.

This diff fixes the base default values of the privacy manifest, and then verified against Apple's validator to make sure the required fields are correct.

Reviewed By: fabiomassimo

Differential Revision: D56294818

fbshipit-source-id: 656917ec4c3452ca5ebaa60dd44efe303f7e0396

Source/PrivacyInfo.xcprivacy

@@ -7,14 +7,16 @@
     LICENSE file in the root directory of this source tree.
 -->
 <plist version="1.0">
-    <dict>
-        <key>NSPrivacyAccessedAPITypes</key>
-        <array/>
-        <key>NSPrivacyCollectedDataTypes</key>
-        <array/>
-        <key>NSPrivacyTracking</key>
-        <false/>
-        <key>NSPrivacyTrackingDomains</key>
-        <array/>
-    </dict>
+<dict>
+	<key>NSPrivacyAccessedAPITypes</key>
+	<array>
+		<dict/>
+	</array>
+	<key>NSPrivacyCollectedDataTypes</key>
+	<array/>
+	<key>NSPrivacyTracking</key>
+	<false/>
+	<key>NSPrivacyTrackingDomains</key>
+	<array/>
+</dict>
 </plist>