Update isSameApp check

Only check uid, without a sandbox sdk exception

This small change involves a major test change since we previously
too permissive in our test setup

Test: NotificationManagerServiceTest
Test: HSUM NotificationManagerServiceTest
Test: SdkSandboxRestrictionsTest
Bug: 396667508
Fixes: 317957802
Flag: EXEMPT bug fix

(cherry picked from commit f5605ae25b15e1f8295e86c431d304e333ce56a4)
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:9931811bc94d5db0d6c17b3e2d18cca2959506a4
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:3d72900800a1bf9667336e40f3f6bdf24f09f295
Merged-In: I2be1537803a83cf44cc605f2850a3bb705b9bf32
Change-Id: I2be1537803a83cf44cc605f2850a3bb705b9bf32