jquery.wikiEditor: change autoIcon() to no longer append version string

Remove use of mw.loader.getVersion, which I'm planning to remove
from the public API. The only valid use case I found of it (not
in WMF repos) is to check if a module exists, for which one can
use mw.loader.getState() already.

The code path here handles with the 'icon' property of a
WikiEditor "toolbar group tool". In other words, the buttons
you can click in the toolbar to open a dialog or insert markup.

I found two ways to reach this code path:

* For the built-in tools and icons that are part of WikiEditor.
  These are all based on OOUI now and no longer use inline styles
  with background-image etc., they are class-based instead, with
  the URLs and language variants handled server-side by RL.

* For user scripts that register a custom tool and icon.
  To try this, copy snippets to the console on an edit page from
  <https://meta.wikimedia.org/wiki/User:Krinkle/Scripts/InsertWikiEditorButton>

  These pass urls as the 'icon' property and thus don't satisfy
  the hasOwn condition in this code. And even if they did, there'd
  be no reason for the module version to be helpful to the thumbnail
  url the user would have passed.

This line of code has existed with the mw.loader.getVersion() call
since the repository's very first commit in 2010 (9d278e8dee).

The worst that can happen is if there are stil some internal icons
hitting this path, they'll be cached for 1 hour instead of 7 days
(per /w/static.php rules in production). For third parties, there
would be no difference and such static paths have no caching by
default either way (outside WMF).

Change-Id: I6ec29abde0085d04b662b56b5ebcc2bd7fa267f8

modules/jquery.wikiEditor.js

@@ -209,7 +209,7 @@
 					if ( src.substr( 0, 7 ) !== 'http://' && src.substr( 0, 8 ) !== 'https://' && src[ 0 ] !== '/' ) {
 						src = path + src;
 					}
-					return src + '?' + mw.loader.getVersion( 'jquery.wikiEditor' );
+					return src;
 				}
 			}
 			return icon;