Use SDK Sandbox process UserHandle for SDK context creation.

In some scenarios application.uid could be not set for RE-SDKs.
For thouse use cases current process (sdk_sandbox) UserHandle should be used.

Without this change SYSTEM (0) user will be used (-1 / PER_USER_RANGE)

Bug: 323267234
Test: CustomizedSdkContextTest from secondary user
Change-Id: I04527c8b89341020460cae1adb1b80269b68fbcd