Update FalukantService and PoliticsView to enhance election data handling

- Modified the FalukantService to use getOpenPolitics instead of getElections for retrieving accessible elections, improving alignment with frontend data display.
- Updated the PoliticsView to handle the response from the application submission more effectively, ensuring that already applied positions remain pre-selected after submission.
- These changes aim to streamline the election data flow and enhance user experience in the application process.

backend/services/falukantService.js

@@ -3510,7 +3510,11 @@ class FalukantService extends BaseService {
                         { model: RegionType, as: 'regionType', attributes: ['labelTr'] }
                     ]
                 },
-                { model: Candidate, as: 'candidates' },
+                { 
+                    model: Candidate, 
+                    as: 'candidates',
+                    required: false
+                },
                 {
                     model: PoliticalOfficeType, as: 'officeType',
                     include: [{ model: PoliticalOfficePrerequisite, as: 'prerequisites' }]
@@ -3569,10 +3573,11 @@ class FalukantService extends BaseService {
             return { applied: [], skipped: electionIds };
         }
 
-        // 3) Ermittle die heute offenen Wahlen, auf die er zugreifen darf
-        //    (getElections liefert id, officeType, region, date, postsToFill, candidates, voted…)
-        const openElections = await this.getElections(hashedUserId);
-        const allowedIds = new Set(openElections.map(e => e.id));
+        // 3) Ermittle die offenen Wahlen, auf die er zugreifen darf
+        //    Verwende getOpenPolitics statt getElections, da getOpenPolitics die gleichen Wahlen
+        //    zurückgibt, die im Frontend angezeigt werden
+        const openPolitics = await this.getOpenPolitics(hashedUserId);
+        const allowedIds = new Set(openPolitics.map(e => e.id));
 
         // 4) Filter alle electionIds auf gültige/erlaubte
         const toTry = electionIds.filter(id => allowedIds.has(id));