feature_flags: Remove remoting feature flag (#29390)

This PR removes the `remoting` feature flag.

The feature is shipped, and we aren't referencing the flag anywhere
anymore.

Release Notes:

- N/A

crates/feature_flags/src/feature_flags.rs

@@ -64,11 +64,6 @@ impl FeatureFlag for PredictEditsRateCompletionsFeatureFlag {
     const NAME: &'static str = "predict-edits-rate-completions";
 }
 
-pub struct Remoting {}
-impl FeatureFlag for Remoting {
-    const NAME: &'static str = "remoting";
-}
-
 pub struct LanguageModels {}
 impl FeatureFlag for LanguageModels {
     const NAME: &'static str = "language-models";