refactor: remove legacy XML tool calling code (getToolDescription) (RooCodeInc#10929)

- Remove getToolDescription() method from MultiSearchReplaceDiffStrategy
- Remove getToolDescription() from DiffStrategy interface
- Remove unused ToolDescription type from shared/tools.ts
- Remove unused eslint-disable directive
- Update test mocks to remove getToolDescription references
- Remove getToolDescription tests from multi-search-replace.spec.ts

Native tools are now defined in src/core/prompts/tools/native-tools/ using
the OpenAI function format. The removed code was dead since XML-style tool
calling was replaced with native tool calling.

Author: hannesrudolph

src/core/webview/__tests__/ClineProvider.spec.ts

@@ -285,7 +285,6 @@ vi.mock("../../../api/providers/fetchers/modelCache", () => ({
 
 vi.mock("../diff/strategies/multi-search-replace", () => ({
 	MultiSearchReplaceDiffStrategy: vi.fn().mockImplementation(() => ({
-		getToolDescription: () => "test",
 		getName: () => "test-strategy",
 		applyDiff: vi.fn(),
 	})),