Add SdkSandboxActivityAuthority

go/sdk-sandbox-activity-authority
Roll-forward of ag/25029620

Bug: 299109198
Test: atest SdkSandboxInstrumentationTest SdkSandboxManagerUnitTest SdkSandboxManagerServiceUnitTest SdkSandboxActivityAuthorityTest
Change-Id: I9dd99445512d8774d84c7876125e2437f4e4a973
4 files changed