Remove watchdog timer logic in ChooserActivity.

This timeout was intended for the deprecated ChooserTargetService,
and as of ag/15644659 we no longer rely on it in the new flow.

Since we're no longer dependent on CTS connections for our
completion conditions, the timeout-handling logic was always fired
both on the "min" and the "max" watchdog periods, apparently
resulting in a spurious additional logDirectShareTargetReceived
call (both with ACTION_DIRECT_SHARE_TARGETS_LOADED_CHOOSER_SERVICE).
The new condition added in ag/15644659 results in an *additional*
spurious log event when the share targets are finished loading,
but as of this CL that load-completion callback will be the sole
place that we perform the logging.

Test: manual / presubmits
Change-Id: Ied1f7c90159d4db42669f0b7e046a9c0a16cb6d0