fix regression how fish_escape_delay_ms is handled

Fish 2.6.0 introduced a regression that keeps setting
`fish_escape_delay_ms` as a uvar from working. This also fixes a related
problem: callbacks generated from the initial loading of universal vars
were not being acted on.

Fixes #4196

src/input_common.cpp

@@ -60,7 +60,6 @@ static int (*interrupt_handler)();
 
 void input_common_init(int (*ih)()) {
     interrupt_handler = ih;
-    update_wait_on_escape_ms();
 }
 
 void input_common_destroy() {}