Fix subscribeTo sometimes not emitting initial value (#2076)

* Add a test for `subscribeTo`

* subscribeTo: Fix initial flow value sometimes not propagated

Co-authored-by: schroda <50052685+schroda@users.noreply.github.com>
Co-authored-by: Syer10 <mitchellptbo@gmail.com>

* lint

---------

Co-authored-by: schroda <50052685+schroda@users.noreply.github.com>
Co-authored-by: Syer10 <mitchellptbo@gmail.com>

server/src/test/kotlin/suwayomi/tachidesk/FlowTest.kt

@@ -0,0 +1,26 @@
+package suwayomi.tachidesk
+
+import graphql.Assert.assertTrue
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.runTest
+import suwayomi.tachidesk.server.subscribeTo
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+import kotlin.test.Test
+
+class FlowTest {
+    @Test
+    fun subscribe() =
+        runTest {
+            (1..1000).forEach { _ ->
+                val testFlow = MutableStateFlow(value = 3)
+                testFlow.first()
+                val latch = CountDownLatch(1)
+                subscribeTo(testFlow, ignoreInitialValue = false) { _ ->
+                    latch.countDown()
+                }
+                assertTrue(latch.await(5, TimeUnit.SECONDS))
+            }
+        }
+}