Add dependency management to GUI tests

[drew2a]

Introduced pytest-dependency and pytest-order packages to manage dependencies between GUI tests. This allows for more controlled execution of test cases, ensuring that certain tests run before others. The test_downloads function is now marked as a dependency for other related test functions, enforcing the order in which they are executed.

Fixes #8010

Refs:

• https://pytest-order.readthedocs.io/en/latest/configuration.html#order-dependencies
• https://github.com/RKrahl/pytest-dependency