Don't include additionalData when en/decrypting with crypto.subtle

Otherwise compatibility with Conversations is broken.
Unfortunately this means that OMEMO won't work on Edge, because it
for some reason requires the additionalData.

References:
* https://github.com/conversejs/converse.js/issues/1187#issuecomment-426276243
* https://stackoverflow.com/questions/42933162/web-crypto-api-using-microsoft-edge-38-14393-0-0/42950731

Fixes #1187

CHANGES.md

@@ -3,7 +3,6 @@
 ## 4.0.2 (Unreleased)
 
 - M4A and WEBM files, when sent as XEP-0066 Out of Band Data, are now playable directly in chat
-- OMEMO fixes for Edge.
 - Updated French and Spanish translations
 - Two new languages supported, [Hindi](https://hosted.weblate.org/languages/hi/conversejs/) and [Romanian](https://hosted.weblate.org/languages/ro/conversejs/)
 - #1187 UTF-8 characters have the wrong encoding when using OMEMO

dist/converse.js

@@ -72906,7 +72906,6 @@ var __WEBPACK_AMD_DEFINE_FACTORY__, __WEBPACK_AMD_DEFINE_ARRAY__, __WEBPACK_AMD_
                 algo = {
             'name': 'AES-GCM',
             'iv': iv,
-            'additionalData': new Uint8Array(1),
             'tagLength': TAG_LENGTH
           },
                 encrypted = await crypto.subtle.encrypt(algo, key, u.stringToArrayBuffer(plaintext)),
@@ -72929,7 +72928,6 @@ var __WEBPACK_AMD_DEFINE_FACTORY__, __WEBPACK_AMD_DEFINE_ARRAY__, __WEBPACK_AMD_
                 algo = {
             'name': "AES-GCM",
             'iv': u.base64ToArrayBuffer(obj.iv),
-            'additionalData': new Uint8Array(1),
             'tagLength': TAG_LENGTH
           };
           return u.arrayBufferToString((await crypto.subtle.decrypt(algo, key_obj, cipher)));

src/converse-omemo.js

@@ -218,7 +218,6 @@
                           algo = {
                               'name': 'AES-GCM',
                               'iv': iv,
-                              'additionalData': new Uint8Array(1),
                               'tagLength': TAG_LENGTH
                           },
                           encrypted = await crypto.subtle.encrypt(algo, key, u.stringToArrayBuffer(plaintext)),
@@ -242,7 +241,6 @@
                           algo = {
                               'name': "AES-GCM",
                               'iv': u.base64ToArrayBuffer(obj.iv),
-                              'additionalData': new Uint8Array(1),
                               'tagLength': TAG_LENGTH
                           }
                     return u.arrayBufferToString(await crypto.subtle.decrypt(algo, key_obj, cipher));