fix: add missing exit statements in integration callback and OAuth files

includes/http.php

@@ -156,3 +156,4 @@ if (!function_exists('fociz_http_request')) {
         ];
     }
 }
+

includes/integrations/jira.php

@@ -308,3 +308,4 @@ function jira_disconnect(int $userId): bool {
     unset($_SESSION["jira_issues_user_{$userId}"]);
     return $stmt->execute([$userId]);
 }
+

includes/integrations/microsoft.php

@@ -257,3 +257,4 @@ function microsoft_disconnect(int $userId): bool {
     $stmt = $db->prepare("DELETE FROM integrations WHERE user_id = ? AND provider = 'OUTLOOK'");
     return $stmt->execute([$userId]);
 }
+