[Glitch] When sending a toot, ensure a CW is only set if the CW field is visible

Partial port of ccc7fe3e1d to glitch-soc

It doesn't ensure the field isn't changed, just that it isn't submitted if
the field isn't visible. Ensuring the field isn't changed would require
reworking the “always show CW field” feature.

app/javascript/flavours/glitch/actions/compose.js

@@ -138,7 +138,8 @@ export function submitCompose(routerHistory) {
   return function (dispatch, getState) {
     let status = getState().getIn(['compose', 'text'], '');
     let media  = getState().getIn(['compose', 'media_attachments']);
-    let spoilerText = getState().getIn(['compose', 'spoiler_text'], '');
+    const spoilers = getState().getIn(['compose', 'spoiler']) || getState().getIn(['local_settings', 'always_show_spoilers_field']);
+    let spoilerText = spoilers ? getState().getIn(['compose', 'spoiler_text'], '') : '';
 
     if ((!status || !status.length) && media.size === 0) {
       return;