Make it possible to toggle TARE developer options page.

Add a flag and API to make it possible to hide/show the
TARE page option in Developer Options.

The setting is for local development and does not need to be transferred between devices.

Bug: 270498386
Bug: 270964794
Test: manually modify flags and check if TARE option shows
Change-Id: I4bea7045c17dbfbcbd973732e4d3c67cca9fe032