Don't send Dolphin version in user agent to Redump

When we added the RetroAchievements integration, we had a discussion
about whether sending version information in the user agent was fine
from a privacy standpoint. We reached the conclusion that it was okay,
but it was conditional on the website having a privacy policy. Neither
incarnation of Redump has that, and Redump also never asked us to send
version information like RetroAchievements did, so let's use a user
agent that just says "Dolphin" when connecting to Redump.

Source/Core/Common/Version.cpp

@@ -19,6 +19,12 @@ namespace Common
 #define BUILD_TYPE_STR ""
 #endif
 
+const std::string& GetEmulatorName()
+{
+  static const std::string emulator_name = EMULATOR_NAME;
+  return emulator_name;
+}
+
 const std::string& GetScmRevStr()
 {
   static const std::string scm_rev_str = EMULATOR_NAME " "

Source/Core/Common/Version.h

@@ -7,6 +7,7 @@
 
 namespace Common
 {
+const std::string& GetEmulatorName();
 const std::string& GetScmDescStr();
 const std::string& GetScmBranchStr();
 const std::string& GetScmRevStr();

Source/Core/DiscIO/VolumeVerifier.cpp

@@ -128,7 +128,7 @@ RedumpVerifier::DownloadStatus RedumpVerifier::DownloadDatfile(const std::string
 
   const std::optional<std::vector<u8>> result =
       request.Get("https://redump.info/datfile/" + system + "/serial,version",
-                  {{"User-Agent", Common::GetScmRevStr()}});
+                  {{"User-Agent", Common::GetEmulatorName()}});
 
   const std::string output_path = GetPathForSystem(system);