fix(password) set input type to "password"

This will make browsers not cache results in cleartext.

Co-authored-by: Tim Dittler <t.dittler@heinlein-support.de>

react/features/room-lock/components/PasswordRequiredPrompt.web.js

                     name = 'lockKey'
                     onChange = { this._onPasswordChanged }
                     shouldFitContainer = { true }
-                    type = 'text'
+                    type = 'password'
                     value = { this.state.password } />
             </div>
         );