Do not store a static instance of AccessibilityManager

Instead this creates an AccessibilityManager per BridgeContext and
stores it within the BridgeContext so that it will not cause leaks.

Bug: 284186358
Test: N/A
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:055e44eb3e64b5052d4765371b6b6995c68d4655)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:365818ae63d6d0048ef03fe44f8a16ae78d8d66b)
Merged-In: I914b70b1b6a503e9a76a0582fa318b0f09c57aaf
Change-Id: I914b70b1b6a503e9a76a0582fa318b0f09c57aaf
3 files changed