tests: add decision flow test

[Cristhianzl]

This pull request includes changes to the src/frontend/tests/core/integrations/Vector Store.spec.ts file, primarily focused on cleaning up and re-enabling previously commented-out test code. The most important changes include re-enabling the test setup and execution steps, ensuring the necessary environment variables are checked, and restoring the test logic for the "Vector Store RAG" feature.

Test setup and execution:

• Re-enabled the checks for necessary environment variables (OPENAI_API_KEY, ASTRA_DB_API_ENDPOINT, ASTRA_DB_APPLICATION_TOKEN).
• Restored the navigation and interaction steps for the "Vector Store RAG" test, including waiting for selectors, handling modals, and interacting with UI elements.

Test logic restoration:

• Re-implemented the logic to handle outdated components, API key inputs, and Astra DB configurations.
• Restored the file upload and execution steps for running the "Vector Store RAG" test, including verifying the test file visibility and running the test commands.
• Re-enabled the steps to interact with the chat playground, including filling inputs and verifying message logs.

[codspeed-hq]

CodSpeed Performance Report

Merging #4384 will degrade performances by 32.89%

_{Comparing cz/fix_tests_ci (a994ca1) with main (7cc497a)}

Summary

⚡ 1 improvements
❌ 1 regressions
✅ 14 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	cz/fix_tests_ci	Change
❌	test_load_flows	874.9 µs	1,303.6 µs	-32.89%
⚡	test_successful_run_with_output_type_debug	527.4 ms	451.4 ms	+16.85%

[anovazzi1]

lgtm