Fixed GetProxyUri() to return a reference

Author: nidietr-MSFT

src/AppInstallerCommonCore/MSStoreDownload.cpp

@@ -913,7 +913,7 @@ namespace AppInstaller::MSStore
                 sfsClientRequest.productRequests = { {std::string{ wuCategoryId }, {}} };
                 if (AppInstaller::Settings::Network().GetProxyUri())
                 {
-                    std::string proxyUri = AppInstaller::Settings::Network().GetProxyUri().value();
+                    const auto& proxyUri = AppInstaller::Settings::Network().GetProxyUri().value();
 
                     sfsClientRequest.proxy = proxyUri;
                     AICLI_LOG(Core, Info, << "Passing proxy to SFS client " << proxyUri);

src/AppInstallerCommonCore/Public/winget/NetworkSettings.h

@@ -16,7 +16,7 @@ namespace AppInstaller::Settings
     {
         static NetworkSettings& Instance();
 
-        const std::optional<std::string> GetProxyUri() const { return m_proxyUri; }
+        const std::optional<std::string>& GetProxyUri() const { return m_proxyUri; }
         // Sets the proxy URI; may do nothing depending on admin settings and group policy
         void SetProxyUri(const std::optional<std::string>& proxyUri);
 
@@ -30,4 +30,4 @@ namespace AppInstaller::Settings
     };
 
     NetworkSettings& Network();
-}
+}