frontend: Assume versioned interface lookup succeeds

The API version middleware will catch an invalid API version and
complete the request before the final handler function executes,
so handler functions can safely get the versioned interface from
the request context.

frontend/frontend.go

@@ -180,7 +180,7 @@ func (f *Frontend) ArmResourceListByResourceGroup(writer http.ResponseWriter, re
 func (f *Frontend) ArmResourceRead(writer http.ResponseWriter, request *http.Request) {
 	ctx := request.Context()
 	logger := ctx.Value(ContextKeyLogger).(*slog.Logger)
-	versionedInterface, _ := ctx.Value(ContextKeyVersion).(api.Version)
+	versionedInterface := ctx.Value(ContextKeyVersion).(api.Version)
 	logger.Info(fmt.Sprintf("%s: ArmResourceRead", versionedInterface))
 
 	// URL path is already lowercased by middleware.
@@ -207,7 +207,7 @@ func (f *Frontend) ArmResourceRead(writer http.ResponseWriter, request *http.Req
 func (f *Frontend) ArmResourceCreateOrUpdate(writer http.ResponseWriter, request *http.Request) {
 	ctx := request.Context()
 	logger := ctx.Value(ContextKeyLogger).(*slog.Logger)
-	versionedInterface, _ := ctx.Value(ContextKeyVersion).(api.Version)
+	versionedInterface := ctx.Value(ContextKeyVersion).(api.Version)
 
 	logger.Info(fmt.Sprintf("%s: ArmResourceCreateOrUpdate", versionedInterface))
 
@@ -252,7 +252,7 @@ func (f *Frontend) ArmResourcePatch(writer http.ResponseWriter, request *http.Re
 func (f *Frontend) ArmResourceDelete(writer http.ResponseWriter, request *http.Request) {
 	ctx := request.Context()
 	logger := ctx.Value(ContextKeyLogger).(*slog.Logger)
-	versionedInterface, _ := ctx.Value(ContextKeyVersion).(api.Version)
+	versionedInterface := ctx.Value(ContextKeyVersion).(api.Version)
 	logger.Info(fmt.Sprintf("%s: ArmResourceDelete", versionedInterface))
 
 	// URL path is already lowercased by middleware.