commands: Read disableFastRender from flag even if it's not changed

Fixes #5353

commands/hugo.go

@@ -219,6 +219,7 @@ func initializeFlags(cmd *cobra.Command, cfg config.Provider) {
 
 	// Will set a value even if it is the default.
 	flagKeysForced := []string{
+		"disableFastRender",
 		"minify",
 	}