fix(web): apply correct key codes to scan codes mapping (#866)

The root cause of the bug is the incorrect keycodes-to-scancodes
mappings. These mappings translated the browser's key codes (like
"KeyA") to OS-specific scancode (OS where the browser runs). However,
that's not exactly what we need to do. We need to map the browser's key
codes to _Windows_ scancodes - the only format that is accepted by _VNC_
and _RDP_) modules.
Let's look at an example for a better understanding. _Safari_ browser
used _Linux_'s _Gecko) mappings as a fallback (because there were no
MacOS-specific mappings). For a given key, _iron-remote-desktop_ was
providing a scancode that did not correspond to the _Windows_ scancode
for that same key. As a result, the `IronVNC` module incorrectly mapped
this scancode to a `KeySym`, which resulted in an incorrect `KeySym` or
`NO_SYMBOL`.

web-client/iron-remote-desktop/src/enums/OS.ts

@@ -1,5 +0,0 @@
-export enum OS {
-    WINDOWS = 'windows',
-    LINUX = 'linux',
-    ANDROID = 'android',
-}

web-client/iron-remote-desktop/src/services/remote-desktop.service.ts

@@ -1,6 +1,5 @@
 import { loggingService } from './logging.service';
 import { scanCode } from '../lib/scancodes';
-import { OS } from '../enums/OS';
 import { ModifierKey } from '../enums/ModifierKey';
 import { LockKey } from '../enums/LockKey';
 import { SessionEventType } from '../enums/SessionEventType';
@@ -329,7 +328,7 @@ export class RemoteDesktopService {
         }
 
         if (!evt.repeat || (!isModifierKey && !isLockKey)) {
-            const keyScanCode = scanCode(evt.code, OS.WINDOWS);
+            const keyScanCode = scanCode(evt.code);
             const unknownScanCode = Number.isNaN(keyScanCode);
 
             if (!this.keyboardUnicodeMode && keyEvent && !unknownScanCode) {
@@ -343,7 +342,7 @@ export class RemoteDesktopService {
                     return;
                 }
 
-                const keyCode = scanCode(evt.key, OS.WINDOWS);
+                const keyCode = scanCode(evt.key);
                 const isUnicodeCharacter = Number.isNaN(keyCode) && evt.key.length === 1;
 
                 if (isUnicodeCharacter && sendAsUnicode) {