m daemon: Pass through RUST_LOG

tree/.local/nu/mullvad.nu

@@ -92,6 +92,10 @@ def "m daemon" [
         ]
     }
 
+    if $env.RUST_LOG? != null {
+        $envs ++= [$"RUST_LOG=($env.RUST_LOG)"]
+    }
+
     if $debug_fw {
         $envs ++= [TALPID_FIREWALL_DEBUG=1]
     }