Role should be 'user' for content specified by the client

This change leads to much more detailed answers in Performance panel.

Bug: 498941727
Change-Id: Iea42219c9f930a44f671547564f97e269dde37b0
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/7736550
Commit-Queue: Jack Franklin <jacktfranklin@chromium.org>
Reviewed-by: Jack Franklin <jacktfranklin@chromium.org>

Author: Liviu Rau

front_end/core/host/AidaGcaTranslation.test.ts

@@ -143,7 +143,7 @@ describe('AidaGcaTranslation', () => {
 
       const expectedGcaRequest = createGcaRequest('chat_console_insights', {
         contents: [
-          {role: 'model', parts: [{text: '[source: src1] Fact 1'}, {text: '[source: src2] Fact 2'}]},
+          {role: 'user', parts: [{text: '[source: src1] Fact 1'}, {text: '[source: src2] Fact 2'}]},
           {role: 'user', parts: [{text: 'Hello'}]},
         ],
       });

front_end/core/host/AidaGcaTranslation.ts

@@ -360,7 +360,7 @@ function gcaCandidateToAidaGenerationSample(candidate: GCA.Candidate): AIDA.Gene
 
 function convertAidaFactsToGcaContent(facts: AIDA.RequestFact[]): GCA.Content {
   return {
-    role: 'model',
+    role: 'user',
     parts: facts.map(fact => {
       return {text: `[source: ${fact.metadata.source}] ${fact.text}`};
     }),