Permissions: Remove duplicate conversion function from PermissionType to String
Permissions: Remove duplicate conversion function from PermissionType to String

The removed function is only used in one place, and is an almost exact
duplicate of PermissionUtil::GetPermissionString. The only difference is
the incorrect strings AudioRecording/VideoRecording instead of
AudioCapture/VideoCapture. This is the only place
AudioRecording/VideoRecording are used in the codebase.

BUG=469221

Review URL: https://codereview.chromium.org/1597303002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#370058}

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