fix(greeter): reimplement regression to hide debug logs during login

- Provide more status feedback
- Allow 2 fprint tries within 10 seconds for DMS-managed PAM
- Updated dms greeter docs

Note: distro-managed PAM takes precedence and may use different limits.
DMS auth changes remain conditional on greetd being installed.

Fixes #2853
Port 1.5

quickshell/Modules/Greetd/GreetdSettings.qml

@@ -219,12 +219,11 @@ Singleton {
         blockWrites: true
         atomicWrites: false
         watchChanges: false
-        printErrors: true
+        printErrors: false
         onLoaded: {
             parseSettings(settingsFile.text());
         }
-        onLoadFailed: error => {
-            log.warn("Failed to load greetd settings:", error);
+        onLoadFailed: {
             root.parseSettings("");
         }
     }