fix(@schematics/angular): preserve Jasmine stub-by-default semantics for bare spies

The refactor-jasmine-vitest schematic previously migrated bare spyOn and spyOnProperty
calls as a direct mechanical rename to vi.spyOn. Since the APIs feature opposing
default behaviors (with jasmine.spyOn stubbing by default and vi.spyOn calling through),
this caused migrated test suites to silently change behavior.

This update structurally analyzes the AST during translation to detect chained strategies,
appending .mockReturnValue(undefined) precisely for bare spies to retain original
Jasmine semantics.

Fixes #33253