feat(expenses): Add delete expense endpoint and functionality

Implements the ability to delete an expense, including its associated items and shares. Also refactors the expense update logic to correctly handle share updates and adds the corresponding API endpoint and mock DB function.

services/mockDb.ts

@@ -1,3 +1,4 @@
+
 import { 
   Condo, Family, Payment, AppSettings, User, AuthResponse, 
   Ticket, TicketComment, ExtraordinaryExpense, Notice, 
@@ -327,6 +328,12 @@ export const CondoService = {
       });
   },
 
+  deleteExpense: async (id: string): Promise<void> => {
+      return request(`/expenses/${id}`, {
+          method: 'DELETE'
+      });
+  },
+
   getExpenseAttachment: async (expenseId: string, attachmentId: string): Promise<any> => {
       return request(`/expenses/${expenseId}/attachments/${attachmentId}`);
   },
@@ -342,4 +349,4 @@ export const CondoService = {
           body: JSON.stringify({ amount, notes: 'PayPal Payment' })
       });
   }
-};
+};