feat(project-finance): implement hierarchical task loading and subtasks retrieval

- Enhanced the project finance controller to support hierarchical loading of tasks, allowing for better aggregation of financial data from parent and subtasks.
- Introduced a new endpoint to fetch subtasks along with their financial details, improving the granularity of task management.
- Updated the frontend to handle subtasks, including UI adjustments for displaying subtasks and their associated financial data.
- Added necessary Redux actions and state management for fetching and displaying subtasks in the finance table.
- Improved user experience by providing tooltips and disabling time estimation for tasks with subtasks, ensuring clarity in task management.

worklenz-frontend/src/api/project-finance-ratecard/project-finance.api.service.ts

@@ -1,7 +1,7 @@
 import { API_BASE_URL } from "@/shared/constants";
 import { IServerResponse } from "@/types/common.types";
 import apiClient from "../api-client";
-import { IProjectFinanceResponse, ITaskBreakdownResponse } from "@/types/project/project-finance.types";
+import { IProjectFinanceResponse, ITaskBreakdownResponse, IProjectFinanceTask } from "@/types/project/project-finance.types";
 
 const rootUrl = `${API_BASE_URL}/project-finance`;
 
@@ -20,6 +20,16 @@ export const projectFinanceApiService = {
         return response.data;
       },
 
+    getSubTasks: async (
+        projectId: string,
+        parentTaskId: string
+      ): Promise<IServerResponse<IProjectFinanceTask[]>> => {
+        const response = await apiClient.get<IServerResponse<IProjectFinanceTask[]>>(
+          `${rootUrl}/project/${projectId}/tasks/${parentTaskId}/subtasks`
+        );
+        return response.data;
+      },
+
     getTaskBreakdown: async (
         taskId: string
       ): Promise<IServerResponse<ITaskBreakdownResponse>> => {