Support partial mutation responses (#954)

In case e.g. a mutation was made which looked like this

myMutation {
  mutationA { ... }
  mutationB { ... }
  mutationC { ... }
}

and mutation A and B succeeded while mutation C failed, the response only included the error of C and the successful mutation data response of A and B was missing

server/src/main/kotlin/suwayomi/tachidesk/graphql/AsDataFetcherResult.kt

@@ -0,0 +1,25 @@
+package suwayomi.tachidesk.graphql
+
+import com.expediagroup.graphql.server.extensions.toGraphQLError
+import graphql.execution.DataFetcherResult
+import mu.KotlinLogging
+
+val logger = KotlinLogging.logger { }
+
+inline fun <T> asDataFetcherResult(block: () -> T): DataFetcherResult<T?> {
+    val result =
+        runCatching {
+            block()
+        }
+
+    if (result.isFailure) {
+        logger.error(result.exceptionOrNull()) { "asDataFetcherResult: failed due to" }
+        return DataFetcherResult.newResult<T?>()
+            .error(result.exceptionOrNull()?.toGraphQLError())
+            .build()
+    }
+
+    return DataFetcherResult.newResult<T?>()
+        .data(result.getOrNull())
+        .build()
+}