Prevent system reset staged installer bypass flag unexpactly

Perform stage installer check and consume bypass flag only when it's
creating stage session and was not calling from system/shell.

Fix: 159412477
Fix: 159684099
Test: atest CtsStagedInstallHostTestCases
Change-Id: Ic5439ad57b3c475d36746b1b36a99618c5b09ad6
1 file changed