fix: simplify error handling for FetchError in various components

frontend/app/pages/dashboard/admin/internships/edit/[id].vue

@@ -33,7 +33,7 @@ async function handleUpdateOfBasicInfo(internship: NewInternship) {
 
         navigateTo("/dashboard/admin/internships");
     } catch (e) {
-        if (e instanceof FetchError && (e.response?.status === 422 || e.response?.status === 400)) {
+        if (e instanceof FetchError) {
             action_error.value = e.response?._data.message;
         }
     } finally {

frontend/app/pages/dashboard/admin/students/edit/[id].vue

@@ -64,7 +64,6 @@ async function saveChanges() {
         navigateTo("/dashboard/admin/students");
     } catch (e) {
         if (e instanceof FetchError) {
-            console.error('Error saving student:', e.response?._data.message);
             alert('Chyba:\n' + e.response?._data.message);
         }
     } finally {
@@ -111,8 +110,6 @@ const deleteStudent = async () => {
     } catch (e) {
         if (e instanceof FetchError) {
             deleteError.value = e.response?._data?.message || 'Chyba pri mazaní študenta.';
-        } else {
-            deleteError.value = 'Neznáma chyba pri mazaní študenta.';
         }
     } finally {
         deleteLoading.value = false;

frontend/app/pages/dashboard/student/internship/create.vue

@@ -1,5 +1,6 @@
 <script setup lang="ts">
 import type { NewInternship } from '~/types/internships';
+import { FetchError } from 'ofetch';
 
 definePageMeta({
     middleware: ['sanctum:auth', 'student-only'],
@@ -25,8 +26,10 @@ async function handleInternshipRegistration(internship: NewInternship) {
         });
 
         navigateTo("/dashboard/student");
-    } catch (e: any) {
-        error.value = e.data?.message as string;
+    } catch (e) {
+        if (e instanceof FetchError) {
+            error.value = e.response?._data.message;
+        }
     } finally {
         loading.value = false;
     }