Rename --no-display to --no-mirror

The option impacts both video and audio playback, so "no display" is not
an appropriate name.

PR #3978 <https://github.com/Genymobile/scrcpy/pull/3978>

app/src/options.c

@@ -52,7 +52,7 @@ const struct scrcpy_options scrcpy_options_default = {
     .fullscreen = false,
     .always_on_top = false,
     .control = true,
-    .display = true,
+    .mirror = true,
     .turn_screen_off = false,
     .key_inject_mode = SC_KEY_INJECT_MODE_MIXED,
     .window_borderless = false,