[Query Copilot V2] Wire and adjust Output bubble with backend communication (#1599)

* Initial wiring of copilot backend and bubble

* Additional changes in explanation bubbles

* Changes based on checks

* test snapshots updated

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Co-authored-by: Predrag Klepic <v-prklepic@microsoft.com>

src/Explorer/QueryCopilot/Shared/QueryCopilotInterfaces.ts

@@ -11,11 +11,13 @@ export interface GenerateSQLQueryResponse {
 enum MessageSource {
   User,
   AI,
+  AIExplanation,
 }
 
 export interface CopilotMessage {
   source: MessageSource;
   message: string;
+  sqlQuery?: string;
   explanation?: string;
 }