Fix luminosity contrast ratio for text in computed tab

Expected Result: Luminosity contrast ratio for 'Dark Gray' text in Computed tab should be greater than or equal to 4.5:1.

User Impact: Low vision users will face difficulty, to identify the static text if it is not meeting the required standard ratio of 4.5:1.

MAS Reference Link: https://aka.ms/MAS1.4.3

Trap ID: 9.1 - https://aka.ms/UnattractiveAppearance

Bug: 379869743
Change-Id: I7f751d9a74fe6fe6eb82442b4d2ddaf739565dba
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6035854
Reviewed-by: Kim-Anh Tran <[email protected]>
Reviewed-by: Yang Guo <[email protected]>
Commit-Queue: Yang Guo <[email protected]>

Author: natashalee

front_end/panels/elements/ComputedStyleWidget.ts

@@ -496,7 +496,7 @@ export class ComputedStyleWidget extends UI.ThrottledWidget.ThrottledWidget {
             'contextmenu', this.handleContextMenuEvent.bind(this, matchedStyles, data.property));
         return html`${traceElement}`;
       }
-      return html`<span style="cursor: text; color: var(--sys-color-token-subtle);">${data.name}</span>`;
+      return html`<span style="cursor: text; color: var(--sys-color-on-surface-subtle);">${data.name}</span>`;
     };
   }