Remove MediaProvider @TestApi

Modules shouldn't have TestApis, as documented in go/android-api-types.
Additionally, nothing depends on these TestApis existing.

Bug: 170395679
Test: m checkapi
Change-Id: Icd99f09f15ebf386adc20b32ea25dc3ba221aab8
Merged-In: Icd99f09f15ebf386adc20b32ea25dc3ba221aab8
(cherry picked from commit 6b3a079be727c2e7c4a85760b1b5de4f85bad414)
1 file changed