Fix a typo in Metric class' regular expression

https://bugs.webkit.org/show_bug.cgi?id=259122

Reviewed by Dewei Zhu.

Fixed the typo.

* Websites/perf.webkit.org/public/v3/models/metric.js:
(Metric):

Canonical link: https://commits.webkit.org/265969@main

Websites/perf.webkit.org/public/v3/models/metric.js

@@ -9,7 +9,7 @@ class Metric extends LabeledObject {
         this._test = object.test;
         this._platforms = [];
 
-        const suffix = this.name().match('([A-z][a-z]+|FrameRate)$')[0];
+        const suffix = this.name().match('([A-Z][a-z]+|FrameRate)$')[0];
         this._unit = {
             'FrameRate': 'fps',
             'Runs': '/s',