Wrap all <Text> in a helper that ensures black color is applied by default

src/view/com/util/PostEmbeds.tsx

@@ -1,15 +1,9 @@
 import React from 'react'
-import {
-  ImageStyle,
-  StyleSheet,
-  StyleProp,
-  Text,
-  View,
-  ViewStyle,
-} from 'react-native'
+import {ImageStyle, StyleSheet, StyleProp, View, ViewStyle} from 'react-native'
 import * as AppBskyEmbedImages from '../../../third-party/api/src/client/types/app/bsky/embed/images'
 import * as AppBskyEmbedExternal from '../../../third-party/api/src/client/types/app/bsky/embed/external'
 import {Link} from '../util/Link'
+import {Text} from '../util/Text'
 import {colors} from '../../lib/styles'
 import {AutoSizedImage} from './images/AutoSizedImage'
 import {ImagesLightbox} from '../../../state/models/shell-ui'
@@ -152,16 +146,16 @@ const styles = StyleSheet.create({
     borderRadius: 8,
     padding: 10,
   },
-  extImage: {
-    // TODO
-  },
+  extImage: {},
   extTitle: {
     fontSize: 16,
     fontWeight: 'bold',
+    color: colors.black,
   },
   extDescription: {
     marginTop: 4,
     fontSize: 15,
+    color: colors.black,
   },
   extUrl: {
     color: colors.gray4,