Fix dkim runtime exception

lib/logic/api_maps/rest_maps/server.dart

@@ -625,38 +625,25 @@ class ServerApi extends ApiMap {
     }
   }
 
-  Future<String> getDkim() async {
+  Future<String?> getDkim() async {
     Response response;
-
+    String? dkim;
     final Dio client = await getClient();
     try {
       response = await client.get('/services/mailserver/dkim');
-    } on DioError catch (e) {
-      print(e.message);
-      throw Exception('No DKIM key found');
-    } finally {
-      close(client);
-    }
-
-    if (response.statusCode == null) {
-      throw Exception('No DKIM key found');
-    }
-
-    if (response.statusCode == HttpStatus.notFound || response.data == null) {
-      throw Exception('No DKIM key found');
-    }
-
-    if (response.statusCode != HttpStatus.ok) {
-      throw Exception('No DKIM key found');
-    }
-
       final Codec<String, String> base64toString = utf8.fuse(base64);
-
+      dkim = base64toString
-    return base64toString
           .decode(response.data)
           .split('(')[1]
           .split(')')[0]
           .replaceAll('"', '');
+    } on DioError catch (e) {
+      print(e.message);
+    } finally {
+      close(client);
+    }
+
+    return dkim;
   }
 
   Future<ApiResponse<RecoveryKeyStatus?>> getRecoveryTokenStatus() async {

lib/logic/cubit/dns_records/dns_records_cubit.dart

@@ -139,7 +139,7 @@ class DnsRecordsCubit
     final String? ipAddress,
     final String? dkimPublicKey,
   ) {
-    if (domainName == null || ipAddress == null || dkimPublicKey == null) {
+    if (domainName == null || ipAddress == null) {
       return [];
     }
     return [
@@ -204,6 +204,7 @@ class DnsRecordsCubit
         type: 'TXT',
         category: DnsRecordsCategory.email,
       ),
+      if (dkimPublicKey != null)
         DesiredDnsRecord(
           name: 'selector._domainkey.$domainName',
           content: dkimPublicKey,

lib/logic/cubit/server_installation/server_installation_repository.dart

@@ -398,7 +398,7 @@ class ServerInstallationRepository {
 
     String dkimRecordString = '';
     try {
-      dkimRecordString = await api.getDkim();
+      dkimRecordString = (await api.getDkim())!;
     } catch (e) {
       print(e);
       rethrow;