refactor(ui): pretty event ai style (#730)

## What type of PR is this?

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/kind cleanup
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/kind documentation
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## What this PR does / why we need it:

TODO

## Which issue(s) this PR fixes:

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Fixes #

ui/src/pages/insightDetail/components/eventAggregator/styles.module.less

@@ -262,22 +262,6 @@
         radial-gradient(ellipse 583px 668px at 436px 8px,
           #ffffff 0%,
           #f5f0ff30 100%);
-      position: relative;
-      overflow: hidden;
-
-      &::before {
-        content: '';
-        position: absolute;
-        top: -50%;
-        left: -50%;
-        width: 200%;
-        height: 200%;
-        background: radial-gradient(circle at center,
-            rgba(149, 128, 247, 0.03) 0%,
-            transparent 70%);
-        animation: rotate 60s linear infinite;
-        pointer-events: none;
-      }
 
       .events_content_diagnosisHeader {
         padding: 12px 16px;