fix: update MarketplaceViewStateManager test to match default isFetching state (#4954)

The test was expecting isFetching to be false in the default state, but the implementation correctly initializes it as true to show a loading state on initial load. Updated the test expectation to match the actual behavior.

webview-ui/src/components/marketplace/__tests__/MarketplaceViewStateManager.spec.ts

@@ -58,7 +58,7 @@ describe("MarketplaceViewStateManager", () => {
 
 			expect(state.allItems).toEqual([])
 			expect(state.displayItems).toEqual([])
-			expect(state.isFetching).toBe(false)
+			expect(state.isFetching).toBe(true)
 			expect(state.activeTab).toBe("mcp")
 			expect(state.filters).toEqual({
 				type: "",