PrivacyIndicators: Test VmCameraMicManager when the feature is enabled.

Restructure VmCameraMicManagerTest to allow its children test class
perform parameterized test when both kPrivacyIndicators is enabled and
disabled.

Also fix a small logic in CloseNotification() when we should close the
notification with the correct id.

Fixed: b:257314539
Change-Id: I26557af16662d56b686bfc87e0db3c5e6a7113b5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4003326
Reviewed-by: Jason Lin <lxj@google.com>
Commit-Queue: Andre Le <leandre@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1069451}