Add removed webview_zygote_socket to 27 mapping file.

Bug: 69390067
Test: manual run of treble_sepolicy_tests
Change-Id: I19252eb743e6527cbe262b1e066a3f67f7186994

private/compat/27.0/27.0.cil

 ;; types removed from current policy
+(type webview_zygote_socket)
 (type reboot_data_file)
 
 (expandtypeattribute (accessibility_service_27_0) true)