Fix invalid flow coroutine context

[ptitjes]

Currently, some flow builders are used alongside with Ktor Http client. However, this makes the flow emissions being done in the wrong coroutine context. channelFlow should be used in these cases.

Othewise, when using Ktor 3.4.0, you will get these kind of exceptions:

java.lang.IllegalStateException: Flow invariant is violated:
		Flow was collected in [RunningInRunTest, kotlinx.coroutines.test.TestCoroutineScheduler@4027879f, kotlinx.coroutines.test.TestScopeKt$TestScope$$inlined$CoroutineExceptionHandler$1@1be6036f, BackgroundWork, CoroutineId(23), "coroutine#23":ScopeCoroutine{Active}@2ce0344d, Dispatchers.IO],
		but emission happened in [RunningInRunTest, kotlinx.coroutines.test.TestCoroutineScheduler@4027879f, kotlinx.coroutines.test.TestScopeKt$TestScope$$inlined$CoroutineExceptionHandler$1@1be6036f, BackgroundWork, CoroutineId(23), kotlinx.coroutines.UndispatchedMarker@1f2e5d3a, "coroutine#23":UndispatchedCoroutine{Active}@63c93a3f, Dispatchers.IO].
		Please refer to 'flow' documentation or use 'flowOn' instead
	at kotlinx.coroutines.flow.internal.SafeCollector_commonKt.checkContext(SafeCollector.common.kt:84)
	at kotlinx.coroutines.flow.internal.SafeCollector.checkContext(SafeCollector.kt:132)
	at kotlinx.coroutines.flow.internal.SafeCollector.emit(SafeCollector.kt:109)
	at kotlinx.coroutines.flow.internal.SafeCollector.emit(SafeCollector.kt:82)
	at me.devnatan.dockerkt.resource.image.ImageResource$pull$1$2.invokeSuspend(ImageResource.kt:46)
	at me.devnatan.dockerkt.resource.image.ImageResource$pull$1$2.invoke(ImageResource.kt)
	at me.devnatan.dockerkt.resource.image.ImageResource$pull$1$2.invoke(ImageResource.kt)
	at io.ktor.client.statement.HttpStatement$execute$2$1.invokeSuspend(HttpStatement.kt:63)
	at io.ktor.client.statement.HttpStatement$execute$2$1.invoke(HttpStatement.kt)
	at io.ktor.client.statement.HttpStatement$execute$2$1.invoke(HttpStatement.kt)
	at kotlinx.coroutines.intrinsics.UndispatchedKt.startUndspatched(Undispatched.kt:66)
	at kotlinx.coroutines.intrinsics.UndispatchedKt.startUndispatchedOrReturn(Undispatched.kt:43)
	at kotlinx.coroutines.BuildersKt__Builders_commonKt.withContext(Builders.common.kt:165)
	at kotlinx.coroutines.BuildersKt.withContext(Unknown Source)
	at io.ktor.client.statement.HttpStatement.execute(HttpStatement.kt:62)
	at io.ktor.client.statement.HttpStatement$execute$1.invokeSuspend(HttpStatement.kt)
	at _COROUTINE._BOUNDARY._(CoroutineDebugging.kt:42)
	at io.ktor.client.statement.HttpStatement.execute(HttpStatement.kt:62)
	at me.devnatan.dockerkt.resource.image.ImageResource$pull$1.invokeSuspend(ImageResource.kt:42)
	...

[ptitjes]

@devnatan btw, you have those errors in Dependabot's MR: https://github.com/devnatan/docker-kotlin/actions/runs/21557264545/job/62115734965?pr=245#step:6:120

[devnatan]

LGTM! Thx!!