fix(shared-video) make placeholder translatable

Also fix capitalization.

lang/main.json

         "shareScreenWarningH1": "If you want to share just your screen:",
         "shareScreenWarningD1": "you need to stop audio sharing before sharing your screen.",
         "shareScreenWarningD2": "you need to stop audio sharing, start screen sharing and check the \"share audio\" option.",
+        "sharedVideoLinkPlaceholder": "YouTube link or direct video link",
         "stopLiveStreaming": "Stop live stream",
         "stopRecording": "Stop recording",
         "stopRecordingWarning": "Are you sure you would like to stop the recording?",

react/features/shared-video/components/native/SharedVideoDialog.js

 import React from 'react';
 
 import { InputDialog } from '../../../base/dialog';
+import { translate } from '../../../base/i18n';
 import { connect } from '../../../base/redux';
 import { ColorPalette } from '../../../base/styles';
-import { defaultSharedVideoLink } from '../../constants';
 import AbstractSharedVideoDialog from '../AbstractSharedVideoDialog';
 
 /**
      * @inheritdoc
      */
     render() {
+        const { t } = this.props;
+
         return (
             <InputDialog
                 contentKey = 'dialog.shareVideoTitle'
                 onSubmit = { this._onSubmitValue }
                 textInputProps = {{
-                    placeholder: defaultSharedVideoLink,
+                    autoCapitalize: 'none',
+                    autoCorrect: false,
+                    placeholder: t('dialog.sharedVideoLinkPlaceholder'),
                     placeholderTextColor: ColorPalette.lightGrey
                 }} />
         );
     }
 }
 
-export default connect()(SharedVideoDialog);
+export default translate(connect()(SharedVideoDialog));

react/features/shared-video/components/web/SharedVideoDialog.js

 import { translate } from '../../../base/i18n';
 import { getFieldValue } from '../../../base/react';
 import { connect } from '../../../base/redux';
-import { defaultSharedVideoLink } from '../../constants';
 import AbstractSharedVideoDialog from '../AbstractSharedVideoDialog';
 
 /**
                     label = { t('dialog.videoLink') }
                     name = 'sharedVideoUrl'
                     onChange = { this._onChange }
-                    placeholder = { defaultSharedVideoLink }
+                    placeholder = { t('dialog.sharedVideoLinkPlaceholder') }
                     shouldFitContainer = { true }
                     type = 'text'
                     value = { this.state.value } />

react/features/shared-video/constants.js

 // @flow
 
-/**
- * Placeholder for web share video input.
- * @type {string}
- */
-export const defaultSharedVideoLink = 'Youtube link or direct video link';
-
 /**
  * Fixed name of the video player fake participant.
  * @type {string}