manager/user: Remove GetAlsIntegrationTimeFileDescriptor for now

It is currently unused and unknown if it will be used. We can add it back later
if we need to, but cannot remove it after stabilizing the API, so let's just
remove it for now

com.steampowered.SteamOSManager1.xml

@@ -27,20 +27,6 @@
     -->
     <property name="AlsCalibrationGain" type="ad" access="read"/>
 
-    <!--
-        GetAlsIntegrationTimeFileDescriptor:
-
-        Get the ALS integration time file descriptor.
-
-        @descriptor: A file descriptor that can be written to to set ALS
-        integration time. Will be null if unable to open file or other error
-        occurred.
-    -->
-    <method name="GetAlsIntegrationTimeFileDescriptor">
-      <arg type="u" name="index" direction="in"/>
-      <arg type="h" name="descriptor" direction="out"/>
-    </method>
-
   </interface>
 
   <!--

src/manager/user.rs

@@ -12,8 +12,7 @@ use tokio::sync::mpsc::{Sender, UnboundedSender};
 use tokio::sync::oneshot;
 use tracing::error;
 use zbus::proxy::Builder;
-use zbus::zvariant::{self, Fd};
-use zbus::{fdo, interface, CacheProperties, Connection, Proxy, SignalContext};
+use zbus::{fdo, interface, zvariant, CacheProperties, Connection, Proxy, SignalContext};
 
 use crate::cec::{HdmiCecControl, HdmiCecState};
 use crate::daemon::user::Command;
@@ -217,18 +216,6 @@ impl AmbientLightSensor1 {
     async fn als_calibration_gain(&self) -> fdo::Result<Vec<f64>> {
         getter!(self, "AlsCalibrationGain")
     }
-
-    async fn get_als_integration_time_file_descriptor(&self, index: u32) -> fdo::Result<Fd> {
-        let m = self
-            .proxy
-            .call_method("GetAlsIntegrationTimeFileDescriptor", &(index))
-            .await
-            .map_err(zbus_to_zbus_fdo)?;
-        match m.body().deserialize::<Fd>() {
-            Ok(fd) => fd.try_to_owned().map_err(to_zbus_fdo_error),
-            Err(e) => Err(zbus_to_zbus_fdo(e)),
-        }
-    }
 }
 
 #[interface(name = "com.steampowered.SteamOSManager1.CpuScaling1")]