https://bugzil.la/1278000 was marked as dupe of https://bugzil.la/577785

Update Wall of Browser Bugs accordingly.
Refs #19670

[ci skip]

docs/_data/browser-bugs.yml

@@ -144,7 +144,7 @@
   summary: >
     Mouse sometimes not within element for purposes of `mouseenter`/`mouseleave` when it's within SVG elements
   upstream_bug: >
-    Mozilla#1278000
+    Mozilla#577785
   origin: >
     Bootstrap#19670