https://webkit.org/b/138201 no longer repros

Wasn't able to reproduce in iOS 9.2.
So remove its entry from the Wall of Browser Bugs.
Refs #14708
[skip sauce]

docs/_data/browser-bugs.yml

@@ -280,16 +280,6 @@
   origin: >
     Bootstrap#14603
 
--
-  browser: >
-    Safari (iOS)
-  summary: >
-    Text input's cursor doesn't move while scrolling the page.
-  upstream_bug: >
-    WebKit#138201, Safari#18819624
-  origin: >
-    Bootstrap#14708
-
 -
   browser: >
     Safari (iOS)