Add elements.css-value-trace known context value

Bug: 406422580
Change-Id: I15db46d85880ab9be201a5c4897f863c0ef6444b
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6403234
Auto-Submit: Philip Pfaffe <[email protected]>
Commit-Queue: Danil Somsikov <[email protected]>
Reviewed-by: Danil Somsikov <[email protected]>
Commit-Queue: Philip Pfaffe <[email protected]>

Author: pfaffe

front_end/ui/visual_logging/KnownContextValues.ts

@@ -1286,6 +1286,7 @@ export const knownContextValues = new Set([
   'elements.css-hint',
   'elements.css-property-doc',
   'elements.css-selector-specificity',
+  'elements.css-value-trace',
   'elements.css-var',
   'elements.dom-breakpoints',
   'elements.dom-creation',