Bridgeless-context BlobModuleTest (#59281) #59281

Summary:

Migrate BlobModuleTest from the deprecated createCatalystContextForTest
helper to createTestReactApplicationContext, so the test builds a bridgeless
context directly. Add the ShadowSoLoader Robolectric shadow and stub the
feature flags before context creation, since the bridgeless context reads
them during init.

Changelog:
[Internal]

Differential Revision: D126574362