Add xcprivacy privacy manifest to macOS framework (flutter#55078)

Create a `PrivacyInfo.xcprivacy` (this name is required) plist and move it to the top-level of the macOS framework bundle.  `NSPrivacyTracking*` and `NSPrivacyCollectedDataTypes` keys are required, but the values are blank.  macOS explicitly does not need the `NSPrivacyAccessedAPITypes` (see more info in flutter/flutter#143381)

You can see on this PR it's copied to the correct path in the framework https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8737163270670636097/+/u/Global_generators/Release-FlutterMacOS.framework/stdout:

```
  adding: FlutterMacOS.xcframework/macos-arm64_x86_64/FlutterMacOS.framework/PrivacyInfo.xcprivacy (deflated 35%)
```

There's no way to test this except to submit a macOS app with this framework to TestFlight.

I can't find a good spot in the engine to validate the structure of the framework output.  I hereby pledge to add a macOS test to the framework post-roll flutter/flutter#155189 � 

iOS framework variant of this PR flutter#48951
Fixes flutter/flutter#131494

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

ci/licenses_golden/licenses_flutter

@@ -46536,6 +46536,7 @@ FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FlutterPlug
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FlutterPluginRegistrarMacOS.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FlutterViewController.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Info.plist
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/PrivacyInfo.xcprivacy
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/AccessibilityBridgeMac.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/AccessibilityBridgeMac.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/AccessibilityBridgeMacTest.mm

shell/platform/darwin/macos/BUILD.gn

@@ -248,6 +248,14 @@ copy("copy_framework_module_map") {
   outputs = [ "$_flutter_framework_dir/Versions/A/Modules/module.modulemap" ]
 }
 
+# Copy privacy manifest. This file is required by Apple for third-party SDKs.
+# See https://developer.apple.com/documentation/bundleresources/privacy_manifest_files
+copy("copy_framework_privacy_manifest") {
+  visibility = [ ":*" ]
+  sources = [ "framework/PrivacyInfo.xcprivacy" ]
+  outputs = [ "$_flutter_framework_dir/PrivacyInfo.xcprivacy" ]
+}
+
 action("copy_framework_headers") {
   script = "//flutter/sky/tools/install_framework_headers.py"
   visibility = [ ":*" ]
@@ -304,6 +312,7 @@ action("_generate_symlinks") {
     ":copy_framework_icu",
     ":copy_framework_info_plist",
     ":copy_framework_module_map",
+    ":copy_framework_privacy_manifest",
     ":copy_license",
   ]
   metadata = {

shell/platform/darwin/macos/framework/PrivacyInfo.xcprivacy

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>NSPrivacyTracking</key>
+	<false/>
+	<key>NSPrivacyTrackingDomains</key>
+	<array/>
+	<key>NSPrivacyCollectedDataTypes</key>
+	<array/>
+</dict>
+</plist>