When we reload a profile, always use the same GUID for it (#2542)

This ensures that settings reload works for profiles w/o GUIDs

Author: zadjii-msft

src/cascadia/TerminalApp/Profile.cpp

@@ -357,7 +357,10 @@ Profile Profile::FromJson(const Json::Value& json)
     }
     else
     {
-        result._guid = Utils::CreateGuid();
+        // Always use the name to generate the temporary GUID. That way, across
+        // reloads, we'll generate the same static GUID.
+        const std::wstring_view name = result._name;
+        result._guid = Utils::CreateV5Uuid(RUNTIME_GENERATED_PROFILE_NAMESPACE_GUID, gsl::as_bytes(gsl::make_span(name)));
 
         TraceLoggingWrite(
             g_hTerminalAppProvider,

src/cascadia/TerminalApp/Profile.h

@@ -16,6 +16,10 @@ Author(s):
 #pragma once
 #include "ColorScheme.h"
 
+// GUID used for generating GUIDs at runtime, for profiles that did not have a
+// GUID specified manually.
+constexpr GUID RUNTIME_GENERATED_PROFILE_NAMESPACE_GUID = { 0xf65ddb7e, 0x706b, 0x4499, { 0x8a, 0x50, 0x40, 0x31, 0x3c, 0xaf, 0x51, 0x0a } };
+
 namespace TerminalApp
 {
     class Profile;