Rename ACTION_CONFIRM_PERMISSIONS -> ACTION_CONFIRM_INSTALL

The old name never really made sense. Now that installations get
confirmed on first start of the app, the old name doesn't make sense at
all anymore.

Test: Installed app via PackageInstallSession (gts-tradefed run
commandAndExit gts-dev -m GtsPackageInstallTestCases)
Change-Id: I3701d34068e2c30002a3b1dddf4aacead8bafaa2