fix(windows): unhandled exception thrown in std::_Xlen_string()

An exception is thrown when built with Visual Studio 16.9:

```
Error Message:
  Unhandled C++ Exception
Stack Trace:
  at std::_Xlen_string() in C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.28.29910\include\xstring:line 2276
  at std::basic_string<char,std::char_traits<char>,std::allocator<char> >::_Reallocate_grow_by<<lambda_9013ee9e23efe4882b67eff5b0ecf103> >() in C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.28.29910\include\xstring:line 4337
  at std::basic_string<char,std::char_traits<char>,std::allocator<char> >::reserve() in C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.28.29910\include\xstring:line 3833
  at ReactTestApp::GetManifest() in D:\a\react-native-test-app\react-native-test-app\example\node_modules\react-native-test-app\windows\ReactTestApp\Manifest.cpp:line 126
  at ReactTestAppTests::ManifestTests::ParseManifestWithComplexInitialProperties() in D:\a\react-native-test-app\react-native-test-app\example\windows\ReactTestAppTests\ManifestTests.cpp:line 70
```

.github/workflows/build.yml

@@ -368,7 +368,7 @@ jobs:
     steps:
       - name: Set up MSBuild
         uses: microsoft/[email protected]
-      - name: Setup VSTest.console.exe
+      - name: Set up VSTest.console.exe
         uses: darenm/Setup-VSTest@v1
       - name: Set up Node.js
         uses: actions/setup-node@v1

windows/ReactTestApp/Manifest.cpp

@@ -9,8 +9,7 @@
 
 #include "Manifest.h"
 
-#include <fstream>
-#include <iostream>
+#include <cstdio>
 
 #include <nlohmann/json.hpp>
 #include <winrt/Windows.Security.Cryptography.Core.h>
@@ -116,16 +115,18 @@ namespace ReactTestApp
 
     std::optional<std::pair<Manifest, std::string>> GetManifest(std::string const &filename)
     {
-        std::string json;
-        {
-            std::ifstream stream(filename);
+        std::FILE *stream = nullptr;
+        if (std::fopen_s(&stream, filename.c_str(), "rb") != 0) {
+            return std::nullopt;
+        }
 
-            stream.seekg(0, std::ios::end);
-            json.reserve(static_cast<size_t>(stream.tellg()));
+        std::string json;
+        std::fseek(stream, 0, SEEK_END);
+        json.resize(std::ftell(stream));
 
-            stream.seekg(0, std::ios::beg);
-            json.assign(std::istreambuf_iterator<char>(stream), {});
-        }
+        std::rewind(stream);
+        std::fread(json.data(), 1, json.size(), stream);
+        std::fclose(stream);
 
         auto j = nlohmann::json::parse(json, nullptr, false);
         if (j.is_discarded()) {