fix: Fix opnsense test, Host.tll now optional and run cargo fmt

opnsense-config-xml/src/data/opnsense.rs

@@ -1223,7 +1223,7 @@ pub struct Host {
     pub rr: String,
     pub mxprio: MaybeString,
     pub mx: MaybeString,
-    pub ttl: MaybeString,
+    pub ttl: Option<MaybeString>,
     pub server: String,
     pub description: Option<String>,
 }
@@ -1238,7 +1238,7 @@ impl Host {
             rr,
             server,
             mxprio: MaybeString::default(),
-            ttl: MaybeString::default(),
+            ttl: Some(MaybeString::default()),
             mx: MaybeString::default(),
             description: None,
         }