Add new add flow for panels

This adds a flow for adding panels that will query consent from the
user. Note that this needs Flags.APP_PANELS_ALL_APPS_ALLOWED for those
panels to show in the first place.

Test: manual, trigger dialog
Test: atest com.android.systemui.controls
Bug: 265180342

Change-Id: I5a0c382f98595daffbd7e4dfe1e52adb43b2f1c5