Update PushProvider API, remove isAvailable(), but instead rely on getDistributors() to eventually return an empty list of Distributors.

libraries/pushproviders/unifiedpush/src/main/kotlin/io/element/android/libraries/pushproviders/unifiedpush/UnifiedPushProvider.kt

@@ -43,17 +43,6 @@ class UnifiedPushProvider @Inject constructor(
     override val index = UnifiedPushConfig.INDEX
     override val name = UnifiedPushConfig.NAME
 
-    override fun isAvailable(): Boolean {
-        val isAvailable = getDistributors().isNotEmpty()
-        return if (isAvailable) {
-            Timber.tag(loggerTag.value).d("UnifiedPush is available")
-            true
-        } else {
-            Timber.tag(loggerTag.value).w("UnifiedPush is not available")
-            false
-        }
-    }
-
     override fun getDistributors(): List<Distributor> {
         return unifiedPushDistributorProvider.getDistributors()
     }

libraries/pushproviders/unifiedpush/src/test/kotlin/io/element/android/libraries/pushproviders/unifiedpush/UnifiedPushProviderTest.kt

@@ -58,7 +58,6 @@ class UnifiedPushProviderTest {
         )
         val result = unifiedPushProvider.getDistributors()
         assertThat(result).containsExactly(Distributor("value", "Name"))
-        assertThat(unifiedPushProvider.isAvailable()).isTrue()
     }
 
     @Test
@@ -70,7 +69,6 @@ class UnifiedPushProviderTest {
         )
         val result = unifiedPushProvider.getDistributors()
         assertThat(result).isEmpty()
-        assertThat(unifiedPushProvider.isAvailable()).isFalse()
     }
 
     @Test