Fix issue with flickering tooltips (#17590)

* Use minimal change to fix flickering

* Remove deprecated unused CSS

Author: timroes

src/ui/public/chrome/directives/kbn_chrome.less

@@ -2,7 +2,10 @@
 @import (reference) "~ui/styles/mixins";
 @import (reference) "~ui/styles/variables";
 
-body { overflow-x: hidden; }
+body {
+  overflow-x: hidden;
+  min-height: 100%;
+}
 
 .app-wrapper {
   .real-flex-parent();

src/ui/public/styles/base.less

@@ -6,14 +6,6 @@
 @import "./react-select";
 @import "./pui_react";
 
-/**
- * 1. Prevent flickering of gauge visualization when tooltip is opened.
- *    https://github.com/elastic/kibana/pull/17227
- */
-.euiBody-hasToolTip {
-  position: static !important; /* 1 */
-}
-
 .small {
   font-size: 0.9em !important;
 }