Attempt to heal settings files damaged by #9962

The bug that caused #9962 resulted in folks getting profiles written to
their settings that didn't contain any identifying information (name or
guid), sometimes multiple times.

These profiles look (somewhat) like this:

```json
{ "colorScheme": "Campbell" },
{},
```

An empty profile serves no purpose -- it shows up in the list as being
named "Default", and it only launches CMD (unless the commandline is the
thing that the user successfully changed.)

We can heal the settings file by simply ignoring those profiles that
have *no identifying information* (a guid or a name that can be
converted into a guid).

Validation
----------
I created a number of profiles that fit this format and made sure that
they were ignored on load and destroyed on save.

src/cascadia/TerminalSettingsModel/CascadiaSettingsSerialization.cpp

@@ -795,6 +795,18 @@ bool CascadiaSettings::_AppendDynamicProfilesToUserSettings()
     return changedFile;
 }
 
+// Function Description:
+// - Given a json serialization of a profile, this function will determine
+//   whether it is "well-formed". We introduced a bug (GH#9962, fixed in GH#9964)
+//   that would result in one or more nameless, guid-less profiles being emitted
+//   into the user's settings file. Those profiles would show up in the list as
+//   "Default" later.
+static bool _IsValidProfileObject(const Json::Value& profileJson)
+{
+    return profileJson.isMember(&*NameKey.begin(), &*NameKey.end()) || // has a name (can generate a guid)
+           profileJson.isMember(&*GuidKey.begin(), &*GuidKey.end()); // or has a guid
+}
+
 // Method Description:
 // - Create a new instance of this class from a serialized JsonObject.
 // Arguments:
@@ -837,7 +849,7 @@ void CascadiaSettings::LayerJson(const Json::Value& json)
 
     for (auto profileJson : _GetProfilesJsonObject(json))
     {
-        if (profileJson.isObject())
+        if (profileJson.isObject() && _IsValidProfileObject(profileJson))
         {
             _LayerOrCreateProfile(profileJson);
         }