Fix Intents init/release in UI tests

[Jharaxus]

As of now, initialization and release of intents are done at the beginning and the end of each Android UI test. Therefore, sometimes when a tests fails it doesn't release its intents (as it is supposed to happen after the assertions), which non-deterministically crashes other tests that then look like they double initialize their intents.

Example of such code:

    @Test
    fun validateProfileButtonGoToTheProfilePage() {

        Intents.init() // here

        // An intent with a name is sent to the activity
        val testIntent =
            Intent(ApplicationProvider.getApplicationContext(), ProfileModifyingActivity::class.java)
        testIntent.putExtra("userId", 1)
        ActivityScenario.launch<ProfileModifyingActivity>(testIntent)

        // Clicking on button
        button.performClick()
        Intents.intended(IntentMatchers.hasComponent(ProfileActivity::class.java.name))

        Intents.release() // here

    }

To fix this, one way could be to use the @Before and @After annotations to initialize and release the intents, therefore avoiding code duplication and enforcing that the release is always done.